Science.gov

Sample records for adhered organic contaminant

  1. Organic contaminant separator

    DOEpatents

    Del Mar, Peter; Hemberger, Barbara J.

    1991-01-01

    A process of sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium by (a) passing an initial aqueous medium including a minor amount of the organic contaminant through a polyolefin tube having an internal diameter of from about 0.01 to about 2.0 millimeters and being of sufficient length to permit the organic contaminant to adhere to the tube, (b) passing a solvent through the tube, said solvent capable of separating the adhered organic contaminant from the tube. Further, a chromatographic apparatus for sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium, said apparatus including a polyolefin tube having an internal diameter of from about 0.01 to about 2.0 millimeters and being of sufficient length to permit an organic contaminant contained within an aqueous medium passed therethrough to adhere to the tube is disclosed.

  2. Organic contaminant separator

    DOEpatents

    Del Mar, P.

    1993-12-28

    A process is presented of sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium by (a) passing an initial aqueous medium including a minor amount of the organic contaminant through a composite tube comprised of a blend of a polyolefin and a polyester, the composite tube having an internal diameter of from about 0.1 to about 2.0 millimeters and being of sufficient length to permit the organic contaminant to adhere to the composite tube, (b) passing a solvent through the composite tube. The solvent is capable of separating the adhered organic contaminant from the composite tube. Further, an extraction apparatus is presented for sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium. The apparatus includes a composite tube comprised of a blend of a polyolefin and a polyester. The composite tube has an internal diameter of from about 0.1 to about 2.0 millimeters and has sufficient length to permit an organic contaminant contained within an aqueous medium passed therethrough to adhere to the composite tube. 2 figures.

  3. Organic contaminant separator

    DOEpatents

    Del Mar, Peter

    1993-01-01

    A process of sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium by (a) passing an initial aqueous medium including a minor amount of the organic contaminant through a composite tube comprised of a blend of a polyolefin and a polyester, the composite tube having an internal diameter of from about 0.1 to about 2.0 millimeters and being of sufficient length to permit the organic contaminant to adhere to the composite tube, (b) passing a solvent through the composite tube, said solvent capable of separating the adhered organic contaminant from the composite tube. Further, an extraction apparatus for sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium, said apparatus including a composite tube comprised of a blend of a polyolefin and a polyester, the composite tube having an internal diameter of from about 0.1 to about 2.0 millimeters and being of sufficient length to permit an organic contaminant contained within an aqueous medium passed therethrough to adhere to the composite tube is disclosed.

  4. Organic contaminant separator

    DOEpatents

    Mar, Peter D.

    1994-01-01

    A process of sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium by (a) passing an initial aqueous medium including a minor amount of the organic contaminant through a composite tube including a polymeric base material selected from the group of polyolefins and polyfluorocarbons and particles of a carbon allotrope material adfixed to the inner wall of the polymeric base material, the composite tube having an internal diameter of from about 0.1 to about 2.0 millimeters and being of sufficient length to permit the organic contaminant to adhere to the composite tube, (b) passing a solvent through the composite tube, said solvent capable of separating the adhered organic contaminant from the composite tube. Further, an extraction apparatus for sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium, said apparatus including a composite tube including a polymeric base material selected from the group of polyolefins and polyfluorocarbons and particles of a carbon allotrope material adfixed to the inner wall of the polymeric base material, the composite tube having an internal diameter of from about 0.1 to about 2.0 millimeters and being of sufficient length to permit an organic contaminant contained within an aqueous medium passed therethrough to adhere to the composite tube is disclosed.

  5. Organic contaminant separator

    DOEpatents

    Del Mar, Peter

    1995-01-01

    A process of sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium by (a) passing an initial aqueous medium including a minor amount of the organic contaminant through a composite tube comprised of a blend of a polyolefin and a polyester, the composite tube having an internal diameter of from about 0.1 to about 2.0 millimeters and being of sufficient length to permit the organic contaminant to adhere to the composite tube, (b) passing a solvent through the composite tube, said solvent capable of separating the adhered organic contaminant from the composite tube. Further, an extraction apparatus for sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium, said apparatus including a composite tube comprised of a blend of a polyolefin and a polyester, the composite tube having an internal diameter of from about 0.1 to about 2.0 millimeters and being of sufficient length to permit an organic contaminant contained within an aqueous medium passed therethrough to adhere to the composite tube is disclosed.

  6. Bacterial adherence and contamination during radiographic processing.

    PubMed

    Bachman, C E; White, J M; Goodis, H E; Rosenquist, J W

    1990-11-01

    Oral fluids are potential contaminants of radiographic processors. This investigation measured bacterial contamination in a radiographic processing room during times of high and low clinical activity and processing effects on five types of microorganisms. Cultures in the clinical setting, during high and low activity, were taken by brain-heart infusion agar plates placed near automatic processors. Site samples were taken of entrance, developer, fixer, water, and exit surfaces. Measurements of processing effects were accomplished by intentional contamination of films run in series through an automatic processor. Site samples were again taken of the processor. In the clinical setting colony-forming units increased with activity. Radiographic processing after intentional contamination decreased colony-forming units on films, but they increased for all processing solutions. Bacteria on radiographic film survived processing. Although processing procedures significantly reduce the number of bacteria on films, the potential for contamination and cross-contamination remains. PMID:2122350

  7. Organic contamination of LDEF

    NASA Technical Reports Server (NTRS)

    Harvey, Gale A.

    1991-01-01

    A brown stain of varying thickness was present on most of the exterior surface of the retrieved Long Duration Exposure Facility (LDEF). Tape lifts of Earth-end LDEF surfaces taken showed that the surface particle cleanliness immediately after retrieval was very good, but faint footprints of the tape strips on the tested surfaces indicated a very faint film was removed by the tape. Solvent wipes of these surfaces showed that the stain was not amenable to standard organic solvent removal. Infrared spectra of optical windows from tray E5 show that the organic film is hydrocarbon in composition, but is not similar to the oil that seeped from tray C12. Very dark and heavy deposits of the stain is present at openings and vents to the interior of LDEF. Heavy brown and blue-green deposits are present in the interior of LDEF where sunlight penetrated through cracks and vent openings. The exterior of LDEF had significant areas painted with a white polyurethane paint for thermal control, and almost all of the interior was painted with a black polyurethane paint. Brown staining is consistent with outgassing of hydrocarbons from these paints by rapid solar UV induced polymerization of the outgassed hydrocarbons when they hit sunlight exposed areas.

  8. Organic contamination of LDEF

    NASA Technical Reports Server (NTRS)

    Harvey, Gale A.

    1992-01-01

    A brown stain of varying thickness was present on most of the exterior surface of the retrieved Long Duration Exposure Facility (LDEF). Tape lifts of Earth-end LDEF surfaces taken in Feb. 1990 showed that the surface particle cleanliness immediately after retrieval was very good, but faint footprints of the tape strips on the tested surfaces indicated a very faint film was removed by the tape. Solvent wipes of these surfaces showed that the stain was not amenable to standard organic solvent removal. Infrared spectra of optical windows from tray E5 and scrapings indicate that the film is primarily of organic composition, but is not similar to the oil that seeped from tray C12. Very dark and heavy deposits of the stain are present at openings and vents to the interior of the LDEF. Heavy brown and blue-green deposits are present in the interior of LDEF where sunlight penetrated through cracks and vent openings. Photographs of the deintegrated LDEF graphically show the stain distribution. The exterior of the LDEF had significant areas painted with a white polyurethane paint for thermal control, and almost all of the interior was painted with a black polyurethane paint for thermal control. The brown staining of the LDEF is consistent with long-term outgassing of hydrocarbons from these paints followed by rapid solar-ultraviolet-induced polymerization of the outgassed hydrocarbons when the outgassed molecules stuck to surfaces exposed to sunlight.

  9. Can health care organizations improve health behavior and treatment adherence?

    PubMed

    Bender, Bruce G

    2014-04-01

    Many Americans are failing to engage in both the behaviors that prevent and those that effectively manage chronic health conditions, including pulmonary disorders, cardiovascular conditions, diabetes, and cancer. Expectations that health care providers are responsible for changing patients' health behaviors often do not stand up against the realities of clinical care that include large patient loads, limited time, increasing co-pays, and restricted access. Organizations and systems that might share a stake in changing health behavior include employers, insurance payers, health care delivery systems, and public sector programs. However, although the costs of unhealthy behaviors are evident, financial resources to address the problem are not readily available. For most health care organizations, the return on investment for developing behavior change programs appears highest when addressing treatment adherence and disease self-management, and lowest when promoting healthy lifestyles. Organizational strategies to improve adherence are identified in 4 categories: patient access, provider training and support, incentives, and information technology. Strategies in all 4 categories are currently under investigation in ongoing studies and have the potential to improve self-management of many chronic health conditions.

  10. Apparatus Removes Organic Contaminants From Water

    NASA Technical Reports Server (NTRS)

    Akse, James R.; Thompson, John

    1994-01-01

    Catalytic-oxidation apparatus removes low-molecular-weight, polar, nonionizable organic contaminants from wastewater. Wastewater stream, previously treated by multifiltration process, pumped through apparatus for removal of trace organic contaminants. After injection of oxygen, flow preheated and enters catalytic reactor, where organic contaminants broken down into carbon dioxide and water. Carbon dioxide and unused oxygen removed in degasser.

  11. Organic Contamination Issues in Life Detection Missions

    NASA Astrophysics Data System (ADS)

    Lin, Ying

    Organic contamination underscores the potential uncertainties in the determination of whether any organic compounds detected by an in-situ instrument are explicitly of extraterrestrial origin. It can also complicate the Planetary Protection assessment of the risk of releasing harmful extraterrestrial material from returned-samples into the earth biosphere. This paper will focus on setting adequate and achievable sample organic contamination limits to meet both life detection goal and planetary protection requirements. Technologies needed to meet sample contamination limits will be identified.

  12. 40 CFR 141.61 - Maximum contaminant levels for organic contaminants.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Maximum contaminant levels for organic... levels for organic contaminants. (a) The following maximum contaminant levels for organic contaminants... with the maximum contaminant level for organic contaminants identified in paragraphs (a) and (c)...

  13. 40 CFR 141.61 - Maximum contaminant levels for organic contaminants.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Maximum contaminant levels for organic... levels for organic contaminants. (a) The following maximum contaminant levels for organic contaminants... with the maximum contaminant level for organic contaminants identified in paragraphs (a) and (c)...

  14. 40 CFR 141.61 - Maximum contaminant levels for organic contaminants.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Maximum contaminant levels for organic... levels for organic contaminants. (a) The following maximum contaminant levels for organic contaminants... with the maximum contaminant level for organic contaminants identified in paragraphs (a) and (c)...

  15. 40 CFR 141.61 - Maximum contaminant levels for organic contaminants.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Maximum contaminant levels for organic... levels for organic contaminants. (a) The following maximum contaminant levels for organic contaminants... with the maximum contaminant level for organic contaminants identified in paragraphs (a) and (c)...

  16. 40 CFR 141.61 - Maximum contaminant levels for organic contaminants.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Maximum contaminant levels for organic... levels for organic contaminants. (a) The following maximum contaminant levels for organic contaminants... with the maximum contaminant level for organic contaminants identified in paragraphs (a) and (c)...

  17. Ecotoxicology of organic contaminants to amphibians

    USGS Publications Warehouse

    Sparling, D.W.; Sparling, Donald W.; Linder, Greg L.; Bishop, Christine A.

    2000-01-01

    The effects of organic contaminants on amphibians are poorly known but of considerable interest. These contaminants include the highly toxic dioxins and furans as well as PCBs, PAHs and organochlorine pesticides. Although these compounds may have lower acute toxicity than dioxins and furans, they have been implicated in several problems associated with genotoxicity, endocrine disruption, malformations and reduced growth. There is evidence that amphibian tadpoles bioaccumulate these organic compounds and may have biological concentrating factors ranging in the hundreds. This chapter reviews what is known about the effects and concentrations of organic contaminants in amphibians and provides recommendations for further research

  18. Photocatalytic Degradation of Organic Contaminants in Water

    EPA Science Inventory

    Photocatalytic treatment of organics, including regulated and contaminants of emerging concern, has been an important area of this field. Details are provided on the mechanism of degradation, reaction intermediates, kinetics, and nanointerfacial adsorption phenomena. The degradat...

  19. Method for testing earth samples for contamination by organic contaminants

    DOEpatents

    Schabron, John F.

    1996-01-01

    Provided is a method for testing earth samples for contamination by organic contaminants, and particularly for aromatic compounds such as those found in diesel fuel and other heavy fuel oils, kerosene, creosote, coal oil, tars and asphalts. A drying step is provided in which a drying agent is contacted with either the earth sample or a liquid extract phase to reduce to possibility of false indications of contamination that could occur when humic material is present in the earth sample. This is particularly a problem when using relatively safe, non-toxic and inexpensive polar solvents such as isopropyl alcohol since the humic material tends to be very soluble in those solvents when water is present. Also provided is an ultraviolet spectroscopic measuring technique for obtaining an indication as to whether a liquid extract phase contains aromatic organic contaminants. In one embodiment, the liquid extract phase is subjected to a narrow and discrete band of radiation including a desired wave length and the ability of the liquid extract phase to absorb that wavelength of ultraviolet radiation is measured to provide an indication of the presence of aromatic organic contaminants.

  20. Method for testing earth samples for contamination by organic contaminants

    DOEpatents

    Schabron, J.F.

    1996-10-01

    Provided is a method for testing earth samples for contamination by organic contaminants, and particularly for aromatic compounds such as those found in diesel fuel and other heavy fuel oils, kerosene, creosote, coal oil, tars and asphalts. A drying step is provided in which a drying agent is contacted with either the earth sample or a liquid extract phase to reduce to possibility of false indications of contamination that could occur when humic material is present in the earth sample. This is particularly a problem when using relatively safe, non-toxic and inexpensive polar solvents such as isopropyl alcohol since the humic material tends to be very soluble in those solvents when water is present. Also provided is an ultraviolet spectroscopic measuring technique for obtaining an indication as to whether a liquid extract phase contains aromatic organic contaminants. In one embodiment, the liquid extract phase is subjected to a narrow and discrete band of radiation including a desired wave length and the ability of the liquid extract phase to absorb that wavelength of ultraviolet radiation is measured to provide an indication of the presence of aromatic organic contaminants. 2 figs.

  1. Longitudinal stability of medication adherence among adolescent solid organ transplant recipients.

    PubMed

    Loiselle, Kristin A; Gutierrez-Colina, Ana M; Eaton, Cyd K; Simons, Laura E; Devine, Katie A; Mee, Laura L; Blount, Ronald L

    2015-06-01

    Solid organ transplantation requires ongoing adherence to immunosuppressants and other medications. Although adolescence is a risk factor for poor medication-taking, little is known about the patterns of adherence within individuals over time. This study aimed to examine the stability of adherence over time using three different assessment techniques. Sixty-six AYA transplant recipients and/or their caregiver completed interviews of adherence at baseline and at least one yr later. Serum immunosuppressant assay levels were collected via medical chart review. Non-adherence percentages based on AYA report, caregiver report, and bioassay did not differ from Time 1 to Time 2. However, correlations for these measures across time were non-significant. Further, the majority of AYAs shifted to a different adherence category from Time 1 to Time 2. Overall, these results demonstrate individual variability in non-adherence over the course of adolescence and young adulthood and highlight the importance of frequent assessment across time for solid organ transplant recipients.

  2. Plant contamination by organic pollutants in phytoremediation.

    PubMed

    Sung, K; Yavuz Corapcioglu, M; Drew, M C; Munster, C L

    2001-01-01

    Phytoremediation is a remediation technique that involves plant uptake, transformation, accumulation, and/or volatilization of soil- and aqueous-phase contaminants or by the stimulation of microbial cometabolic activity in the rhizosphere of the plant. Even when the principal mechanism is by stimulation of bacteria, any resultant plant contamination cannot be overlooked. For the purpose of modeling, a two-compartment plant model has been developed. The model divides the plant into the shoot compartment (which can be harvested) and the root compartment (into which contaminants can accumulate). Numerical experiments were conducted to investigate model behavior and to determine important parameters affecting plant contamination. Johnsongrass [Sorghum halepense (L.) Pers.] was used to evaluate the model behavior. The contaminants TNT (2,4,6,-trinitrotoluene) and chrysene were selected on the basis of their contrasting aqueous-phase solubilities. The results indicate that plant contamination and soil remediation by plants depend on soil properties such as soil organic carbon content, the physicochemical properties of the contaminants such as the octanol-water partition coefficient, and plant properties. The most important factor affecting plant contamination is bioavailability. As bioavailability increased, the concentrations in root and shoot compartments were predicted to increase. Microbial activities and plant contamination are closely related, which suggests that plants and microorganisms can have complementary roles in phytoremediation.

  3. Organic contaminants in onsite wastewater treatment systems

    USGS Publications Warehouse

    Conn, K.E.; Siegrist, R.L.; Barber, L.B.; Brown, G.K.

    2007-01-01

    Wastewater from thirty onsite wastewater treatment systems was sampled during a reconnaissance field study to quantify bulk parameters and the occurrence of organic wastewater contaminants including endocrine disrupting compounds in treatment systems representing a variety of wastewater sources and treatment processes and their receiving environments. Bulk parameters ranged in concentrations representative of the wide variety of wastewater sources (residential vs. non-residential). Organic contaminants such as sterols, surfactant metabolites, antimicrobial agents, stimulants, metal-chelating agents, and other consumer product chemicals, measured by gas chromatography/mass spectrometry were detected frequently in onsite system wastewater. Wastewater composition was unique between source type likely due to differences in source water and chemical usage. Removal efficiencies varied by engineered treatment type and physicochemical properties of the contaminant, resulting in discharge to the soil treatment unit at ecotoxicologically-relevant concentrations. Organic wastewater contaminants were detected less frequently and at lower concentrations in onsite system receiving environments. Understanding the occurrence and fate of organic wastewater contaminants in onsite wastewater treatment systems will aid in minimizing risk to ecological and human health.

  4. Impact of Organic Contamination on Some Aquatic Organisms

    PubMed Central

    Yasser, El-Nahhal; Shawkat, El-Najjar; Samir, Afifi

    2015-01-01

    Background: Contamination of water systems with organic compounds of agricultural uses pose threats to aquatic organisms. Carbaryl, chlorpyrifos, and diuron were considered as model aquatic pollutants in this study. The main objective of this study was to characterize the toxicity of organic contamination to two different aquatic organisms. Materials and Methods: Low concentrations (0.0–60 µmol/L) of carbaryl, diuron and very low concentration (0.0–0.14 µmol/L) of chlorpyrifos and their mixtures were tested against fish and Daphnia magna. Percentage of death and immobilization were taken as indicators of toxicity. Results: Toxicity results to fish and D. magna showed that chlorpyrifos was the most toxic compound (LC50 to fish and D. magna are 0.08, and 0.001 µmol/L respectively), followed by carbaryl (LC50 to fish and D. magna are 43.19 and 0.031 µmol/L), while diuron was the least toxic one (LC50 values for fish and D. magna are 43.48 and 32.11 µmol/L respectively). Mixture toxicity (binary and tertiary mixtures) showed antagonistic effects. Statistical analysis showed a significant difference among mixture toxicities to fish and D. magma. Conclusion: Fish and D. magam were sensitive to low concentrations. These data suggest potent threats to aquatic organisms from organic contamination. PMID:26862260

  5. A systematic review of patient self-reported barriers of adherence to antihypertensive medications using the world health organization multidimensional adherence model.

    PubMed

    AlGhurair, Suliman A; Hughes, Christine A; Simpson, Scot H; Guirguis, Lisa M

    2012-12-01

    Multiple barriers can influence adherence to antihypertensive medications. The aim of this systematic review was to determine what adherence barriers were included in each instrument and to describe the psychometric properties of the identified surveys. Barriers were characterized using the World Health Organization (WHO) Multidimensional Adherence Model with patient, condition, therapy, socioeconomic, and health care system/team-related barriers. Five databases (Medline, Embase, Health and Psychological Instruments, CINHAL, and International Pharmaceutical Abstracts [IPA]) were searched from 1980 to September 2011. Our search identified 1712 citations; 74 articles met inclusion criteria and 51 unique surveys were identified. The Morisky Medication Adherence Scale was the most commonly used survey. Only 20 surveys (39%) have established reliability and validity evidence. According to the WHO Adherence Model domains, patient-related barriers were most commonly addressed, while condition, therapy, and socioeconomic barriers were underrepresented. The complexity of adherence behavior requires robust self-report measurements and the inclusion of barriers relevant to each unique patient population and intervention.

  6. Monitoring Pharmacy Student Adherence to World Health Organization Hand Hygiene Indications Using Radio Frequency Identification.

    PubMed

    Decker, Andrew S; Cipriano, Gabriela C; Tsouri, Gill; Lavigne, Jill E

    2016-04-25

    Objective. To assess and improve student adherence to hand hygiene indications using radio frequency identification (RFID) enabled hand hygiene stations and performance report cards. Design. Students volunteered to wear RFID-enabled hospital employee nametags to monitor their adherence to hand-hygiene indications. After training in World Health Organization (WHO) hand hygiene methods and indications, student were instructed to treat the classroom as a patient care area. Report cards illustrating individual performance were distributed via e-mail to students at the middle and end of each 5-day observation period. Students were eligible for individual and team prizes consisting of Starbucks gift cards in $5 increments. Assessment. A hand hygiene station with an RFID reader and dispensing sensor recorded the nametag nearest to the station at the time of use. Mean frequency of use per student was 5.41 (range: 2-10). Distance between the student's seat and the dispenser was the only variable significantly associated with adherence. Student satisfaction with the system was assessed by a self-administered survey at the end of the study. Most students reported that the system increased their motivation to perform hand hygiene as indicated. Conclusion. The RFID-enabled hand hygiene system and benchmarking reports with performance incentives was feasible, reliable, and affordable. Future studies should record video to monitor adherence to the WHO 8-step technique.

  7. Monitoring Pharmacy Student Adherence to World Health Organization Hand Hygiene Indications Using Radio Frequency Identification.

    PubMed

    Decker, Andrew S; Cipriano, Gabriela C; Tsouri, Gill; Lavigne, Jill E

    2016-04-25

    Objective. To assess and improve student adherence to hand hygiene indications using radio frequency identification (RFID) enabled hand hygiene stations and performance report cards. Design. Students volunteered to wear RFID-enabled hospital employee nametags to monitor their adherence to hand-hygiene indications. After training in World Health Organization (WHO) hand hygiene methods and indications, student were instructed to treat the classroom as a patient care area. Report cards illustrating individual performance were distributed via e-mail to students at the middle and end of each 5-day observation period. Students were eligible for individual and team prizes consisting of Starbucks gift cards in $5 increments. Assessment. A hand hygiene station with an RFID reader and dispensing sensor recorded the nametag nearest to the station at the time of use. Mean frequency of use per student was 5.41 (range: 2-10). Distance between the student's seat and the dispenser was the only variable significantly associated with adherence. Student satisfaction with the system was assessed by a self-administered survey at the end of the study. Most students reported that the system increased their motivation to perform hand hygiene as indicated. Conclusion. The RFID-enabled hand hygiene system and benchmarking reports with performance incentives was feasible, reliable, and affordable. Future studies should record video to monitor adherence to the WHO 8-step technique. PMID:27170822

  8. Monitoring Pharmacy Student Adherence to World Health Organization Hand Hygiene Indications Using Radio Frequency Identification

    PubMed Central

    Decker, Andrew S.; Cipriano, Gabriela C.; Tsouri, Gill

    2016-01-01

    Objective. To assess and improve student adherence to hand hygiene indications using radio frequency identification (RFID) enabled hand hygiene stations and performance report cards. Design. Students volunteered to wear RFID-enabled hospital employee nametags to monitor their adherence to hand-hygiene indications. After training in World Health Organization (WHO) hand hygiene methods and indications, student were instructed to treat the classroom as a patient care area. Report cards illustrating individual performance were distributed via e-mail to students at the middle and end of each 5-day observation period. Students were eligible for individual and team prizes consisting of Starbucks gift cards in $5 increments. Assessment. A hand hygiene station with an RFID reader and dispensing sensor recorded the nametag nearest to the station at the time of use. Mean frequency of use per student was 5.41 (range: 2-10). Distance between the student’s seat and the dispenser was the only variable significantly associated with adherence. Student satisfaction with the system was assessed by a self-administered survey at the end of the study. Most students reported that the system increased their motivation to perform hand hygiene as indicated. Conclusion. The RFID-enabled hand hygiene system and benchmarking reports with performance incentives was feasible, reliable, and affordable. Future studies should record video to monitor adherence to the WHO 8-step technique. PMID:27170822

  9. Phytoremediation of organic contaminants in soil and groundwater.

    PubMed

    Reichenauer, Thomas G; Germida, James J

    2008-01-01

    Phytoremediation is an emerging technology for the clean-up of sites contaminated with hazardous chemicals. The term phytoremediation refers to a number of technologies that use photoautotrophic vascular plants for the remediation of sites contaminated with inorganic and organic contaminants. Phytoremediation of organic contaminants can be organized by considering 1) the green liver concept, which elucidates the metabolism of contaminants in planta versus that of contaminants ex planta (e.g. rhizosphere), 2) processes that lead to complete degradation (mineralization) of contaminants as opposed to those that only lead to partial degradation or transformation, and 3) active plant uptake versus passive processes (e.g. sorption). Understanding of these processes needs an interdisciplinary approach involving chemists, biologists, soil scientists, and environmentalists. This Review presents the basic concepts of phytoremediation of organic contaminants in soil and groundwater using selected contaminants as examples.

  10. Competitive sorption of organic contaminants in chalk

    NASA Astrophysics Data System (ADS)

    Graber, E. R.; Borisover, M.

    2003-12-01

    In the Negev desert, Israel, a chemical industrial complex is located over fractured Eocene chalk formations where transfer of water and solutes between fracture voids and matrix pores affects migration of contaminants in the fractures due to diffusion into the chalk matrix. This study tests sorption and sorption competition between contaminants in the chalk matrix to make it possible to evaluate the potential for contaminant attenuation during transport in fractures. Single solute sorption isotherms on chalk matrix material for five common contaminants ( m-xylene, ametryn, 1,2-dichloroethane, phenanthrene, and 2,4,6-tribromophenol) were found to be nonlinear, as confirmed in plots of Kd versus initial solution concentration. Over the studied concentration ranges, m-xylene Kd varied by more than a factor of 100, ametryn Kd by a factor of 4, 1,2-dichloroethane Kd by more than a factor of 3, phenanthrene Kd by about a factor of 2, and 2,4,6-tribromophenol Kd by a factor of 10. It was earlier found that sorption is to the organic matter component of the chalk matrix and not to the mineral phases (Chemosphere 44 (2001) 1121). Nonlinear sorption isotherms indicate that there is at least some finite sorption domain. Bi-solute competition experiments with 2,4,6-tribromophenol as the competitor were designed to explore the nature of the finite sorption domain. All of the isotherms in the bi-solute experiments are more linear than in the single solute experiments, as confirmed by smaller variations in Kd as a function of initial solution concentration. For both m-xylene and ametryn, there is a small nonlinear component or domain that was apparently not susceptible to competition by 2,4,6-tribromophenol. The nonlinear sorption domain(s) is best expressed at low solution concentrations. Inert-solvent-normalized single and bi-solute sorption isotherms demonstrate that ametryn undergoes specific force interactions with the chalk sorbent. The volume percent of phenanthrene

  11. Natural biodegradation of organic contaminants in groundwater

    SciTech Connect

    McNab, W W; Rice, D W

    1998-09-23

    There has recently been a growing awareness that natural processes are degrading contaminants of concern, and that the contribution these natural processes make to achieving cleanup goals needs to be formally considered during site-specific cleanup. Historical case data from a large number of releases has been used to evaluate the expectation for natural attenuation to contribute to the cleanup of petroleum hydrocarbons and chlorinated solvents. The use of historical case data has several advantages, among them: 1) sites can reduce characterization costs by sharing information on key hydrogeologic parameters controlling contaminant fate and transport, and 2) standard reference frameworks can be developed that individual sites can use as a basis of comparison regarding plume behavior. Definition of cleanup times must take into account basic constraints imposed by natural laws governing the transport and natural degradation process of petroleum hydrocarbons. The actual time to reach groundwater cleanup goals is determined by these laws and the limitations on residual subsurface contamination attenuation rates, through either active or natural biological processes. These limitations will practically constrain the time to achieve low concentration cleanup goals. Recognition is needed that sites will need to be transitioned to remediation by natural processes at some point following implementation of active remediation options. The results of an analysis of approximately 1800 California and 600 Texas fuel hydrocarbon (FHC) releases and 2.50 chlorinated volatile organic compound (CVOC) plumes will be summarized. Plume lengths and natural biodegradation potential were evaluated. For FHC releases, 90% of benzene groundwater plumes were less than 280 feet in length and evidence of natural biodegradation was found to be present at all sites studied in detail. For CVOC releases, source strength and groundwater flow velocity are dominant factors controlling groundwater plume

  12. Organics in water contamination analyzer, phase 1

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The requirements which would result in identifying the components of an automatic analytical system for the analysis of specific organic compounds in the space station potable water supply are defined. The gas chromatographic system for such an analysis is limited to commercially available off-the-shelf hardware and includes the sample inlet, an ionization detector, capillary columns as well as computerized compound identification. The sampling system will be a special variation of the purge and trap Tenax mode using six-port valves and a 500 microliter water sample. Capillary columns used for the separating of contaminants will be bonded phase fused silica with a silicone stationary phase. Two detectors can be used: photoionization and far ultraviolet, since they are sensitive and compatible with capillary columns. A computer system evaluation and program with the principle of compound identification based on the retention index is presented.

  13. 40 CFR 141.50 - Maximum contaminant level goals for organic contaminants.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Maximum contaminant level goals for organic contaminants. 141.50 Section 141.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.50 Maximum contaminant level goals for...

  14. 40 CFR 141.50 - Maximum contaminant level goals for organic contaminants.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Maximum contaminant level goals for organic contaminants. 141.50 Section 141.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.50 Maximum contaminant level goals for...

  15. 40 CFR 141.50 - Maximum contaminant level goals for organic contaminants.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Maximum contaminant level goals for organic contaminants. 141.50 Section 141.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.50 Maximum contaminant level goals for...

  16. 40 CFR 141.50 - Maximum contaminant level goals for organic contaminants.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Maximum contaminant level goals for organic contaminants. 141.50 Section 141.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.50 Maximum contaminant level goals for...

  17. 40 CFR 141.50 - Maximum contaminant level goals for organic contaminants.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Maximum contaminant level goals for organic contaminants. 141.50 Section 141.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.50 Maximum contaminant level goals for...

  18. MICROFRACTURE SURFACE GEOCHEMISTRY AND ADHERENT MICROBIAL POPULATION METABOLISM IN TCE-CONTAMINATED COMPETENT BEDROCK

    EPA Science Inventory

    A TCE-contaminated competent bedrock site in Portsmouth, NH was used to determine if a relation existed between microfracture (MF) surface geochemistry and the ecology and metabolic activity of attached microbes relative to terminal electron accepting processes (TEAPs) and TCE bi...

  19. Method and apparatus for destroying organic contaminants in aqueous liquids

    DOEpatents

    Donaldson, Terrence L.; Wilson, James H.

    1993-01-01

    A method and apparatus for destroying organic contaminants, such as trichloroethylene, in aqueous liquids, such as groundwater, utilizing steam stripping integrated with biodegradation. The contaminated aqueous liquid is fed into a steam stripper causing the volatilization of essentially all of the organic contaminants and a portion of the aqueous liquid. The majority of the aqueous liquid is discharged from the steam stripper. The volatilized vapors are then condensed to the liquid phase and introduced into a bioreactor. The bioreactor contains methanotrophic microorganisms which convert the organic contaminants into mainly carbon dioxide. The effluent from the bioreactor is then recycled back to the steam stripper for further processing.

  20. Method and apparatus for destroying organic contaminants in aqueous liquids

    DOEpatents

    Donaldson, T.L.; Wilson, J.H.

    1993-09-21

    A method and apparatus for destroying organic contaminants, such as trichloroethylene, in aqueous liquids, such as groundwater, utilizing steam stripping integrated with biodegradation. The contaminated aqueous liquid is fed into a steam stripper causing the volatilization of essentially all of the organic contaminants and a portion of the aqueous liquid. The majority of the aqueous liquid is discharged from the steam stripper. The volatilized vapors are then condensed to the liquid phase and introduced into a bioreactor. The bioreactor contains methanotrophic microorganisms which convert the organic contaminants into mainly carbon dioxide. The effluent from the bioreactor is then recycled back to the steam stripper for further processing. 2 figures.

  1. Method for treatment of soils contaminated with organic pollutants

    DOEpatents

    Wickramanayake, Godage B.

    1993-01-01

    A method for treating soil contaminated by organic compounds wherein an ozone containing gas is treated with acid to increase the stability of the ozone in the soil environment and the treated ozone applied to the contaminated soil to decompose the organic compounds. The soil may be treated in situ or may be removed for treatment and refilled.

  2. [Development of an electronic device to organize medications and promote treatment adherence].

    PubMed

    Vieira, Liliana Batista; Ramos, Celso de Ávila; Castello, Matheus de Barros; Nascimento, Lorenzo Couto do

    2016-04-01

    This article describes the development of an electronic prototype to organize medications - the Electronic System for Personal and Controlled Use of Medications (Sistema Eletrônico de Uso Personalizado e Controlado de Medicamentos, SUPERMED). The prototype includes a drawer containing 1 month's supply of medicines, sound and visual medication timers, and a memory card for recording the times when the box was opened/closed (scheduled and unscheduled). This information is later transferred to a computer. Evolutionary prototyping was used to develop SUPERMED with the Arduino platform and C programming. To read alarm and box opening/closing data, software was developed in Java. Once the alarms are programmed (ideally by a health care professional), no additional adjustments are required by the patient. The prototype was tested during 31 days by the developers, with satisfactory functioning. The system seems adequate to organize medications and facilitate adherence to treatment. New studies will be carried out to validate and improve the prototype.

  3. [Development of an electronic device to organize medications and promote treatment adherence].

    PubMed

    Vieira, Liliana Batista; Ramos, Celso de Ávila; Castello, Matheus de Barros; Nascimento, Lorenzo Couto do

    2016-04-01

    This article describes the development of an electronic prototype to organize medications - the Electronic System for Personal and Controlled Use of Medications (Sistema Eletrônico de Uso Personalizado e Controlado de Medicamentos, SUPERMED). The prototype includes a drawer containing 1 month's supply of medicines, sound and visual medication timers, and a memory card for recording the times when the box was opened/closed (scheduled and unscheduled). This information is later transferred to a computer. Evolutionary prototyping was used to develop SUPERMED with the Arduino platform and C programming. To read alarm and box opening/closing data, software was developed in Java. Once the alarms are programmed (ideally by a health care professional), no additional adjustments are required by the patient. The prototype was tested during 31 days by the developers, with satisfactory functioning. The system seems adequate to organize medications and facilitate adherence to treatment. New studies will be carried out to validate and improve the prototype. PMID:27657186

  4. Aqueous adsorption and removal of organic contaminants by carbon nanotubes.

    PubMed

    Yu, Jin-Gang; Zhao, Xiu-Hui; Yang, Hua; Chen, Xiao-Hong; Yang, Qiaoqin; Yu, Lin-Yan; Jiang, Jian-Hui; Chen, Xiao-Qing

    2014-06-01

    Organic contaminants have become one of the most serious environmental problems, and the removal of organic contaminants (e.g., dyes, pesticides, and pharmaceuticals/drugs) and common industrial organic wastes (e.g., phenols and aromatic amines) from aqueous solutions is of special concern because they are recalcitrant and persistent in the environment. In recent years, carbon nanotubes (CNTs) have been gradually applied to the removal of organic contaminants from wastewater through adsorption processes. This paper reviews recent progress (145 studies published from 2010 to 2013) in the application of CNTs and their composites for the removal of toxic organic pollutants from contaminated water. The paper discusses removal efficiencies and adsorption mechanisms as well as thermodynamics and reaction kinetics. CNTs are predicted to have considerable prospects for wider application to wastewater treatment in the future. PMID:24657369

  5. Organic Contamination Baseline Study on NASA JSC Astromaterial Curation Gloveboxes

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Allton, J. H.; Allen, C. C.; Burkett, P. J.

    2013-01-01

    Future planned sample return missions to carbon-rich asteroids and Mars in the next two decades will require strict handling and curation protocols as well as new procedures for reducing organic contamination. After the Apollo program, astromaterial collections have mainly been concerned with inorganic contamination [1-4]. However, future isolation containment systems for astromaterials, possibly nitrogen enriched gloveboxes, must be able to reduce organic and inorganic cross-contamination. In 2012, a baseline study was orchestrated to establish the current state of organic cleanliness in gloveboxes used by NASA JSC astromaterials curation labs that could be used as a benchmark for future mission designs.

  6. Inorganic and organic contaminants in Alaskan shorebird eggs.

    PubMed

    Saalfeld, David T; Matz, Angela C; McCaffery, Brian J; Johnson, Oscar W; Bruner, Phil; Lanctot, Richard B

    2016-05-01

    Many shorebird populations throughout North America are thought to be declining, with potential causes attributed to habitat loss and fragmentation, reduced prey availability, increased predation, human disturbance, and increased exposure to environmental pollutants. Shorebirds may be particularly vulnerable to contaminant exposure throughout their life cycle, as they forage primarily on invertebrates in wetlands, where many contaminants accumulate disproportionately in the sediments. Therefore, it is important to document and monitor shorebird populations thought to be at risk and assess the role that environmental contaminants may have on population declines. To investigate potential threats and provide baseline data on shorebird contaminant levels in Alaskan shorebirds, contaminant concentrations were evaluated in shorebird eggs from 16 species residing in seven geographic distinct regions of Alaska. Similar to previous studies, low levels of most inorganic and organic contaminants were found, although concentrations of several inorganic and organic contaminants were higher than those of previous studies. For example, elevated strontium levels were observed in several species, especially black oystercatcher (Haematopus bachmani) sampled in Prince William Sound, Alaska. Additionally, contaminant concentrations varied among species, with significantly higher concentrations of inorganic contaminants found in eggs of pectoral sandpiper (Calidris melanotos), semipalmated sandpiper (Calidris pusilla), black oystercatcher, and bar-tailed godwit (Limosa lapponica). Similarly, significantly higher concentrations of some organic contaminants were found in the eggs of American golden plover (Pluvialis dominica), black-bellied plover (Pluvialis squatarola), pacific golden plover (Pluvialis fulva), bar-tailed godwit, and semipalmated sandpiper. Despite these elevated levels, current concentrations of contaminants in shorebird eggs suggest that breeding environments are

  7. Inorganic and organic contaminants in Alaskan shorebird eggs.

    PubMed

    Saalfeld, David T; Matz, Angela C; McCaffery, Brian J; Johnson, Oscar W; Bruner, Phil; Lanctot, Richard B

    2016-05-01

    Many shorebird populations throughout North America are thought to be declining, with potential causes attributed to habitat loss and fragmentation, reduced prey availability, increased predation, human disturbance, and increased exposure to environmental pollutants. Shorebirds may be particularly vulnerable to contaminant exposure throughout their life cycle, as they forage primarily on invertebrates in wetlands, where many contaminants accumulate disproportionately in the sediments. Therefore, it is important to document and monitor shorebird populations thought to be at risk and assess the role that environmental contaminants may have on population declines. To investigate potential threats and provide baseline data on shorebird contaminant levels in Alaskan shorebirds, contaminant concentrations were evaluated in shorebird eggs from 16 species residing in seven geographic distinct regions of Alaska. Similar to previous studies, low levels of most inorganic and organic contaminants were found, although concentrations of several inorganic and organic contaminants were higher than those of previous studies. For example, elevated strontium levels were observed in several species, especially black oystercatcher (Haematopus bachmani) sampled in Prince William Sound, Alaska. Additionally, contaminant concentrations varied among species, with significantly higher concentrations of inorganic contaminants found in eggs of pectoral sandpiper (Calidris melanotos), semipalmated sandpiper (Calidris pusilla), black oystercatcher, and bar-tailed godwit (Limosa lapponica). Similarly, significantly higher concentrations of some organic contaminants were found in the eggs of American golden plover (Pluvialis dominica), black-bellied plover (Pluvialis squatarola), pacific golden plover (Pluvialis fulva), bar-tailed godwit, and semipalmated sandpiper. Despite these elevated levels, current concentrations of contaminants in shorebird eggs suggest that breeding environments are

  8. Organic contaminants in direct coal liquefaction--a preliminary assessment.

    PubMed

    Tanita, R; Telesca, D; Walker, J; Berardinelli, S

    1980-11-01

    Area samples taken at two coal liquefaction facilities were analyzed by either gas chromatography or gas chromatography/mass spectrometry to identify the types of organic contaminants to which workers may be exposed. Results indicate that the contaminants consisted primarily of one or two ring low-molecular weight aromatic compounds.

  9. REDUCTIVE DEHALOGENATION OF ORGANIC CONTAMINANTS IN SOILS AND GROUND WATER

    EPA Science Inventory

    Introduction and large scale production of synthetic halogenated organic chemicals over the last 50 years has resulted in a group of contaminants which tend to persist in the environment and resist both biotic and abiotic degradation. The low solubility of these types of contamin...

  10. ELECTROCHEMICAL DEGRADATION OF ORGANIC CONTAMINANTS IN WATER AND SEDIMENTS

    EPA Science Inventory

    Electrochemical degradation (ECD) utilizes high redox potential at the anode and low redox potential at the cathode to oxidize and/or reduce organic and inorganic contaminants. EDC of Trichloroethylene (TCE), although theoretically possible, has not been experimentally proven. Th...

  11. Recent Discoveries and the Ultimate Fate of Organic Contaminants

    EPA Science Inventory

    With very few exceptions, the common organic contaminants in soils, sediments, and ground water can be transformed or entirely degraded by oxidation or reduction reactions that are either carried through direct involvement with microorganisms, or indirectly through abiotic reacti...

  12. USING ZERO-VALENT METAL NANOPARTICLES TO REMEDIATE ORGANIC CONTAMINANTS

    EPA Science Inventory

    The transport of organic contaminants down the soil profile constitutes a serious threat to the quality of ground water. Zero-valent metals are considered innocuous abiotic agents capable of mediating decontamination processes in terrestrial systems. In this investigation, ze...

  13. SEQUESTRATION OF HYDROPHOBIC ORGANIC CONTAMINANTS BY GEOSORBENTS. (R822626)

    EPA Science Inventory

    The chemical interactions of hydrophobic organic contaminants (HOCs) with soils and sediments (geosorbents) may result in strong binding and slow subsequent release rates that significantly affect remediation rates and endpoints. The underlying physical and chemical phenomena ...

  14. Interactions of organic contaminants with mineral-adsorbed surfactants

    USGS Publications Warehouse

    Zhu, L.; Chen, B.; Tao, S.; Chiou, C.T.

    2003-01-01

    Sorption of organic contaminants (phenol, p-nitrophenol, and naphthalene) to natural solids (soils and bentonite) with and without myristylpyridinium bromide (MPB) cationic surfactant was studied to provide novel insight to interactions of contaminants with the mineral-adsorbed surfactant. Contaminant sorption coefficients with mineral-adsorbed surfactants, Kss, show a strong dependence on surfactant loading in the solid. At low surfactant levels, the Kss values increased with increasing sorbed surfactant mass, reached a maximum, and then decreased with increasing surfactant loading. The Kss values for contaminants were always higher than respective partition coefficients with surfactant micelles (Kmc) and natural organic matter (Koc). At examined MPB concentrations in water the three organic contaminants showed little solubility enhancement by MPB. At low sorbed-surfactant levels, the resulting mineral-adsorbed surfactant via the cation-exchange process appears to form a thin organic film, which effectively "adsorbs" the contaminants, resulting in very high Kss values. At high surfactant levels, the sorbed surfactant on minerals appears to form a bulklike medium that behaves essentially as a partition phase (rather than an adsorptive surface), with the resulting Kss being significantly decreased and less dependent on the MPB loading. The results provide a reference to the use of surfactants for remediation of contaminated soils/sediments or groundwater in engineered surfactant-enhanced washing.

  15. Interactions of organic contaminants with mineral-adsorbed surfactants.

    PubMed

    Zhu, Lizhong; Chen, Baoliang; Tao, Shu; Chiou, Cary T

    2003-09-01

    Sorption of organic contaminants (phenol, p-nitrophenol, and naphthalene) to natural solids (soils and bentonite) with and without myristylpyridinium bromide (MPB) cationic surfactant was studied to provide novel insightto interactions of contaminants with the mineral-adsorbed surfactant. Contaminant sorption coefficients with mineral-adsorbed surfactants, Kss, show a strong dependence on surfactant loading in the solid. At low surfactant levels, the Kss values increased with increasing sorbed surfactant mass, reached a maximum, and then decreased with increasing surfactant loading. The Kss values for contaminants were always higher than respective partition coefficients with surfactant micelles (Kmc) and natural organic matter (Koc). At examined MPB concentrations in water the three organic contaminants showed little solubility enhancement by MPB. At low sorbed-surfactant levels, the resulting mineral-adsorbed surfactant via the cation-exchange process appears to form a thin organic film, which effectively "adsorbs" the contaminants, resulting in very high Kss values. At high surfactant levels, the sorbed surfactant on minerals appears to form a bulklike medium that behaves essentially as a partition phase (rather than an adsorptive surface), with the resulting Kss being significantly decreased and less dependent on the MPB loading. The results provide a reference to the use of surfactants for remediation of contaminated soils/sediments or groundwater in engineered surfactant-enhanced washing.

  16. Dissolved Organic Matter and Emerging Contaminants in Urban Stream Ecosystems

    NASA Astrophysics Data System (ADS)

    Kaushal, S. S.; Findlay, S.; Groffman, P.; Belt, K.; Delaney, K.; Sides, A.; Walbridge, M.; Mayer, P.

    2009-05-01

    We investigated the effects of urbanization on the sources, bioavailability and forms of natural and anthropogenic organic matter found in streams located in Maryland, U.S.A. We found that the abundance, biaoavailability, and enzymatic breakdown of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and dissolved organic phosphorus (DOP) increased in streams with increasing watershed urbanization suggesting that organic nutrients may represent a growing form of nutrient loading to coastal waters associated with land use change. Organic carbon, nitrogen, and phosphorus in urban streams were elevated several-fold compared to forest and agricultural streams. Enzymatic activities of stream microbes in organic matter decomposition were also significantly altered across watershed land use. Chemical characterization suggested that organic matter in urban streams originated from a variety of sources including terrestrial, sewage, and in-stream transformation. In addition, a characterization of emerging organic contaminants (polyaromatic cyclic hydrocarbons, organochlorine pesticides, and polybrominated diphenyl ether flame retardents), showed that organic contaminants and dissolved organic matter increase with watershed urbanization and fluctuate substantially with changing climatic conditions. Elucidating the emerging influence of urbanization on sources, transport, and in-stream transformation of organic nutrients and contaminants will be critical in unraveling the changing role of organic matter in urban degraded and restored stream ecosystems.

  17. SALT-OVERLY SENSITIVE5 Mediates Arabidopsis Seed Coat Mucilage Adherence and Organization through Pectins.

    PubMed

    Griffiths, Jonathan S; Tsai, Allen Yi-Lun; Xue, Hui; Voiniciuc, Cătălin; Sola, Krešimir; Seifert, Georg J; Mansfield, Shawn D; Haughn, George W

    2014-05-01

    Interactions between cell wall polymers are critical for establishing cell wall integrity and cell-cell adhesion. Here, we exploit the Arabidopsis (Arabidopsis thaliana) seed coat mucilage system to examine cell wall polymer interactions. On hydration, seeds release an adherent mucilage layer strongly attached to the seed in addition to a nonadherent layer that can be removed by gentle agitation. Rhamnogalacturonan I (RG I) is the primary component of adherent mucilage, with homogalacturonan, cellulose, and xyloglucan constituting minor components. Adherent mucilage contains rays composed of cellulose and pectin that extend above the center of each epidermal cell. CELLULOSE SYNTHASE5 (CESA5) and the arabinogalactan protein SALT-OVERLY SENSITIVE5 (SOS5) are required for mucilage adherence through unknown mechanisms. SOS5 has been suggested to mediate adherence by influencing cellulose biosynthesis. We, therefore, investigated the relationship between SOS5 and CESA5. cesa5-1 seeds show reduced cellulose, RG I, and ray size in adherent mucilage. In contrast, sos5-2 seeds have wild-type levels of cellulose but completely lack adherent RG I and rays. Thus, relative to each other, cesa5-1 has a greater effect on cellulose, whereas sos5-2 mainly affects pectin. The double mutant cesa5-1 sos5-2 has a much more severe loss of mucilage adherence, suggesting that SOS5 and CESA5 function independently. Double-mutant analyses with mutations in MUCILAGE MODIFIED2 and FLYING SAUCER1 that reduce mucilage release through pectin modification suggest that only SOS5 influences pectin-mediated adherence. Together, these findings suggest that SOS5 mediates adherence through pectins and does so independently of but in concert with cellulose synthesized by CESA5.

  18. Treating contaminated organics using the DETOX process

    SciTech Connect

    Elsberry, K.D.; Dhooge, P.M.

    1993-05-01

    Waste matrices containing organics, radionuclides, and metals pose difficult problems in waste treatment and disposal when the organic compounds and/or metals are considered to be hazardous. This paper describes the results of bench-scale studies of DETOX applied to the components of liquid mixed wastes, with the goal of establishing parameters for designing a prototype waste treatment unit. Apparent organic reaction rate orders and the dependence of apparent reaction rate on solution composition and the contact area were measured for vacuum pump oil scintillation fluids, and trichloroethylene. Reaction rate was superior in chloride-based solutions and was proportional to the contact area above about 2% w/w loading of organic. Oxidations in a 4-liter volume, mixed bench-top reactor have given destruction efficiencies of 99.9999 + % for common organics. Reaction rates achieved in the mixed bench-top reactor were one to two orders of magnitude greater than had been achieved in unmixed reactions; a thoroughly mixed reactor should be capable of oxidizing 10 to 100 + grams of organic per liter-hour. Results are also presented on the solvation efficiency of DETOX for mercury, cerium, and neodymium, and for removal/destruction of organics sorbed on vermiculite. The next stage of development will be converting the bench-top unit to continuous processing.

  19. Remediation of soil from lead-contaminated kindergartens reduces the amount of lead adhering to children's hands.

    PubMed

    Nielsen, Jesper B; Kristiansen, Jesper

    2005-05-01

    Risk related to contaminated soil is based on the oral intake of soil and dust among children. This exposure is a consequence of mouthing behaviour, which exposes children to whatever adheres to their hands or toys. This project compared hand exposure of children to lead following outdoor playground activities before and after an intervention. The intervention consisted of replacement of contaminated top soil from the most intensively used playground areas and coverage of bare soil with wood chips or grass. We included children from three kindergartens: one with very low levels of lead in soil and two kindergartens with an average lead concentrations in soil of 100-200 mg/kg. Measurements of lead in soil 5-7 weeks after interventions in two kindergartens verified that the interventions had effectively reduced the potential exposure to lead from the most intensively used areas of the playgrounds. The average lead concentration in soil after intervention was below 10 mg/kg. We found a good agreement between the average concentration of lead in soil and the amount of lead on the hands of the children. Thus, the exposure marker worked and had the advantage compared to a blood sample, that we could evaluate the effect of the interventions shortly after they were accomplished using a noninvasive method. The amount of lead on the hands measured in one of the two kindergartens after the remediation (0.73 microg) was not significantly different from the control kindergarten (0.58 microg). Children from the second kindergarten still had higher median exposures to lead (1.29 microg), but a large overlap existed with several children having lower amounts of lead on their hands than some children from the control kindergarten. Large variations in the amount of lead on hands were observed. Variations may reflect true differences in concentrations of lead in soil, but may also reflect different behavior and playing patterns. Our study demonstrated, that it was possible in a cost

  20. Method for detecting organic contaminants in water supplies

    DOEpatents

    Dooley, Kirk J.; Barrie, Scott L.; Buttner, William J.

    1999-01-01

    A system for detecting organic contaminants in water supplies. A sampling unit is employed which includes a housing having at least one opening therein and a tubular member positioned within the housing having a central passageway surrounded by a side wall. The side wall is made of a composition designed to absorb the contaminants. In use, the sampling unit is immersed in a water supply. The water supply contacts the tubular member through the opening in the housing, with any contaminants being absorbed into the side wall of the tubular member. A carrier gas is then passed through the central passageway of the tubular member. The contaminants will diffuse out of the side wall and into the central passageway where they will subsequently combine with the carrier gas, thereby yielding a gaseous product. The gaseous product is then analyzed to determine the amount and type of contaminants therein.

  1. Method for detecting organic contaminants in water supplies

    DOEpatents

    Dooley, K.J.; Barrie, S.L.; Buttner, W.J.

    1999-08-24

    A system is described for detecting organic contaminants in water supplies. A sampling unit is employed which includes a housing having at least one opening therein and a tubular member positioned within the housing having a central passageway surrounded by a side wall. The side wall is made of a composition designed to absorb the contaminants. In use, the sampling unit is immersed in a water supply. The water supply contacts the tubular member through the opening in the housing, with any contaminants being absorbed into the side wall of the tubular member. A carrier gas is then passed through the central passageway of the tubular member. The contaminants will diffuse out of the side wall and into the central passageway where they will subsequently combine with the carrier gas, thereby yielding a gaseous product. The gaseous product is then analyzed to determine the amount and type of contaminants therein. 5 figs.

  2. Surfactant-enhanced remediation of organic contaminated soil and water.

    PubMed

    Paria, Santanu

    2008-04-21

    Surfactant based remediation technologies for organic contaminated soil and water (groundwater or surface water) is of increasing importance recently. Surfactants are used to dramatically expedite the process, which in turn, may reduce the treatment time of a site compared to use of water alone. In fact, among the various available remediation technologies for organic contaminated sites, surfactant based process is one of the most innovative technologies. To enhance the application of surfactant based technologies for remediation of organic contaminated sites, it is very important to have a better understanding of the mechanisms involved in this process. This paper will provide an overview of the recent developments in the area of surfactant enhanced soil and groundwater remediation processes, focusing on (i) surfactant adsorption on soil, (ii) micellar solubilization of organic hydrocarbons, (iii) supersolubilization, (iv) density modified displacement, (v) degradation of organic hydrocarbon in presence surfactants, (vi) partitioning of surfactants onto soil and liquid organic phase, (vii) partitioning of contaminants onto soil, and (viii) removal of organics from soil in presence of surfactants. Surfactant adsorption on soil and/or sediment is an important step in this process as it results in surfactant loss reduced the availability of the surfactants for solubilization. At the same time, adsorbed surfactants will retained in the soil matrix, and may create other environmental problem. The biosurfactants are become promising in this application due to their environmentally friendly nature, nontoxic, low adsorption on to soil, and good solubilization efficiency. Effects of different parameters like the effect of electrolyte, pH, soil mineral and organic content, soil composition etc. on surfactant adsorption are discussed here. Micellar solubilization is also an important step for removal of organic contaminants from the soil matrix, especially for low aqueous

  3. Bioavailability of sediment-bound contaminants to marine organisms

    SciTech Connect

    Brown, B. |

    1993-09-01

    The bioavailability of sediment-bound contaminants to marine organisms indicates that there exists a potential for transfer of these contaminants through marine food webs to commercial fisheries products consumed by humans. However, there has been relatively little effort to combine and synthesize data on chemical/biological interactions between benthic animals and seagrasses and the sediments in which they reside on the one hand, and on the chemistry of bioaccumulation on the other. This report provides a conceptual basis for an approach to bioavailability and biomagnification of sediment-bound contaminants that reviews biological and chemical approaches.

  4. Clostridium difficile toxin CDT hijacks microtubule organization and reroutes vesicle traffic to increase pathogen adherence.

    PubMed

    Schwan, Carsten; Kruppke, Anna S; Nölke, Thilo; Schumacher, Lucas; Koch-Nolte, Friedrich; Kudryashev, Mikhail; Stahlberg, Henning; Aktories, Klaus

    2014-02-11

    Clostridium difficile causes antibiotic-associated diarrhea and pseudomembranous colitis by the actions of Rho-glucosylating toxins A and B. Recently identified hypervirulent strains, which are associated with increased morbidity and mortality, additionally produce the actin-ADP-ribosylating toxin C. difficile transferase (CDT). CDT depolymerizes actin, causes formation of microtubule-based protrusions, and increases pathogen adherence. Here we show that CDT-induced protrusions allow vesicle traffic and contain endoplasmic reticulum tubules, connected to microtubules via the calcium sensor Stim1. The toxin reroutes Rab11-positive vesicles containing fibronectin, which is involved in bacterial adherence, from basolateral to the apical membrane sides in a microtubule- and Stim1-dependent manner. The data yield a model of C. difficile adherence regulated by actin depolymerization, microtubule restructuring, subsequent Stim1-dependent Ca(2+) signaling, vesicle rerouting, and secretion of ECM proteins to increase bacterial adherence.

  5. Detecting and Quantifying Organic Contaminants in Sediments with NMR

    NASA Astrophysics Data System (ADS)

    Fay, E. L.; Knight, R. J.

    2015-12-01

    Nuclear magnetic resonance (NMR) methods have the potential to detect and monitor free-phase organic contaminants in sediments, both in the laboratory and in the field. NMR directly detects signal from hydrogen-bearing fluids; the signal amplitude is proportional to the total amount of hydrogen present, while the signal decay rate provides information about fluid properties and interactions with the surrounding sediments. Contrasting relaxation times (T2) or diffusion coefficients (D) allow the separation of water signal from contaminant signal. In this work, we conduct a laboratory study to assess the use of NMR measurements to detect and quantify diesel, gasoline, crude oil, and tri-chloroethylene in sediments. We compare the T2 distributions for sediments containing only water, only contaminant, and both water and contaminant, confirming that the identification and quantification of contaminants using T2 data alone is limited by overlapping water and contaminant T2 distributions in some sediments. We leverage the contrast between the diffusion coefficient of water and that of diesel and crude oil to separate contaminant signal from water signal in D-T2 maps. D-T2 distributions are measured both using a pulsed gradient method and a static gradient method similar to methods used with logging tools, allowing us to compare the ability of each method to quantify diesel and crude oil when water is also present. There is the potential to apply these methods to characterize and monitor contaminated sites using commercially available NMR logging tools.

  6. [Cyanobacteria as indicators of organic contamination].

    PubMed

    Peinador, M

    1999-09-01

    In two Costa Rican rivers used as receptors for domestic sewage, treated by primary stabilization ponds, were taken a total of 28 samplings located at the pond exit and at three different sites in each river: 100 m before the ponds discharge, at the discharge and 100 m after the discharge. These sampling were done for a five and a half years including dry and rainy seasons. In each sampling site, samples were collected of five different substrates: stones, submerge and semi submerge vegetation, tree trunks or sticks, water and artificial substrates. For each sample were used two types of artificial cultures, WC and BG110. A total of 55 cyanobacteria species isolations were obtained, belonging to a 26 genera, between these the most common were Phormidium with nine species, Microcystis with five species, Leptolyngbya and Pseudanabaena with four species each and Oscillatoria with three species. More cyanobacteria species were isolated in water substrate and less isolations in tree trunks and submerge vegetation. Konvophoron, Cyanarcus and Pilgeria only were isolate from water samples inoculated in culture media WC and in few opportunities, while three Leptolyngbya species and four Phormidium species were isolated very often. At the stabilization ponds Phormidium sp4 was dominant in 25 of 28 sampling while in the last others were the chlorophycea I. In this study were observed an increase in the frequency of cyanobacteria at the higher contamination places, and a species substitution between different sampling points. There were no biomass studies, therefore is not possible to relate between different cyanobacteria species and some specific types of water quality.

  7. Apparatus for treatment of soils contaminated with organic pollutants

    DOEpatents

    Wickramanayake, Godage B.

    1993-01-01

    An apparatus for treating soil contaminated by organic compounds wherein an ozone containing gas is treated with acid to increase the stability of the ozone in the soil environment and the treated ozone applied to the contaminated soil in a manner adapted to decompose the organic compounds; one embodiment of the apparatus comprises a means to supply ozone as a gas-ozone mixture, a stability means to treat ozone obtained from the supply and distribution means to apply the stabilized gas-ozone to soil. The soil may be treated in situ or may be removed for treatment and refilled.

  8. Soil adherence to human skin

    SciTech Connect

    Driver, J.H.; Konz, J.J.; Whitmyre, G.K. )

    1989-12-01

    Dermal exposure to soils contaminated with toxic chemicals represents a potential public health hazard. These soils, contaminated with chemicals such as PCBs and dioxins, may be found at various locations throughout the US. Furthermore, dermal contact with pesticide-containing particles and contaminated soil particles is of importance for exposures to agricultural workers who reenter fields after pesticide application. With respect to dermal exposure to pesticide-contaminated particulate matter, several occurrences of human toxicity to ethyl parathion in citrus groves have been reported. These exposures resulted from dermal contact with high concentrations of the toxic transformation product paraoxon in soil dust contaminated as a result of application of pesticide to the overhead foliage of trees. To assess dermal exposure to chemically-contaminated soil at sites of concern, dermal adherence of soil must be determined prior to the assessment of dermal absorption. The purpose of the experiment reported herein was to determine the amount of soil (mg/cm{sup 2}) that adheres to adult hands under various soil conditions. These conditions include the type of soil, the organic content of the soil, and the particle size of the soil.

  9. STABLE CHLORINE ISOTOPE ANALYSIS OF CHLORINATED ORGANIC CONTAMINANTS

    EPA Science Inventory

    The biogeochemical cycling of chlorinated organic contaminants in the environment is often difficult to understand because of the complex distributions of these compounds and variability of sources. To address these issues from an isotopic perspective, we have measured the, 37Cl...

  10. Adherence to the Food and Agricultural Organization guidelines on trypanocide usage among cattle farmers in Itezhi tezhi, Central Zambia.

    PubMed

    Mbewe, Njelembo J; Sitali, Lungowe; Namangala, Boniface; Michelo, Charles

    2015-04-15

    Trypanocides will continue to play an important role in the control of tsetse fly transmitted trypanosomosis now and in the near future. The drugs are mostly administered by farmers without any veterinary supervision leading to misuse and under dosing of medication, and these could be factors that promote trypanocidal drug resistance (TDR) development. In order to delay or prevent TDR, the Food and Agriculture Organization (FAO) recommended guidelines on trypanocide use. It is not known if these recommended guidelines are adhered to in Itezhi tezhi district of Zambia. A survey was undertaken to examine how socio-economic and environmental factors were associated with adherence to the recommended guidelines on trypanocide use in Itezhi tezhi, Central Zambia. Ninety farmers who use trypanocides were interviewed using a questionnaire to collect their socio-economic characteristics (age, education in years, cattle herd size, competence on trypanocide use and their access to extension on trypanocide use) and trypanocide usage practices while crush pens which they use were stratified according to location, whether in the Game Management Area (GMA) (Mutenda, Itumbi, Kapulwe and Banachoongo) or non-GMA (Iyanda, New Ngoma and Shinampamba) as an environmental factor. Associations and measures of associations to adherence of FAO guidelines were determined. The results showed that 25.6% of the farmers adhered to guidelines by FAO on trypanocide use and that none of the socio-economic factors under investigation were significantly associated with it. Further the farmers that used crush pens that were in the GMA had an 80% reduction in the likelihood of adhering to the FAO guidelines on trypanocide use than those that used crush pens in the non-GMA (AOR 0.20, 95% CI: 0.05-0.81, P=0.02). There was low adherence to the recommended FAO guidelines on trypanocide use and it was associated with the location of the crush pen whether in the GMA or not, as an environmental factor. With

  11. Temporal trends in organic contaminant bioaccumulation in Boston Harbor

    SciTech Connect

    Hall, M.P.; Connor, M.S.; Downey, P.C.

    1995-12-31

    Since 1987 the MWRA has used in situ caged mussels (Mytilus edulis) to assess organic contaminant (PAHs, PCBs, organochlorine pesticides) bioaccumulation resulting from the primary treatment discharge of its Deer Island POTW. Results indicate a substantial reduction in many contaminants, most notably the Low Molecular Weight (petrogenic) PAHs which are clearly associated with the Deer Island discharge. NOAA `Mussel Watch` and other fish tissue contaminant data are used to support the observation of these decreases. Effluent water quality data and concurrent mussel body burden data from dirty and clean control sites are used to interpret the trends and elucidate the contamination sources. During the same time frame histopathological analyses of winter flounder collected in proximity to the Deer Island discharge have shown a marked reduction in liver lesions and other contaminant related diseases. More recently (since 1992) slight elevations in chlordane, dieldrin, and total DDTs have been noted in mussel, flounder, and lobster tissue collected from Boston Harbor and Massachusetts Bay. The authors discuss the possibility that remobilization of contaminants from the sediments may be a source of this apparent increase.

  12. Biochar: a green sorbent to sequester acidic organic contaminants

    NASA Astrophysics Data System (ADS)

    Sigmund, Gabriel; Kah, Melanie; Sun, Huichao; Hofmann, Thilo

    2015-04-01

    Biochar is a carbon rich product of biomass pyrolysis that exhibits a high sorption potential towards a wide variety of inorganic and organic contaminants. Because it is a valuable soil additive and a potential carbon sink that can be produced from renewable resources, biochar has gained growing attention for the development of more sustainable remediation strategies. A lot of research efforts have been dedicated to the sorption of hydrophobic contaminants and metals to biochar. Conversely, the understanding of the sorption of acidic organic contaminants remains limited, and questions remain on the influence of biochar characteristics (e.g. ash content) on the sorption behaviour of acidic organic contaminants. To address this knowledge gap, sorption batch experiments were conducted with a series of structurally similar acidic organic contaminants covering a range of dissociation constant (2,4-D, MCPA, 2,4-DB and triclosan). The sorbents selected for experimentation included a series of 10 biochars covering a range of characteristics, multiwalled carbon nanotubes as model for pure carbonaceous phases, and an activated carbon as benchmark. Overall, sorption coefficient [L/kg] covered six orders of magnitude and generally followed the order 2,4-D < MCPA < 2,4-DB < triclosan. Combining comprehensive characterization of the sorbents with the sorption dataset allowed the discussion of sorption mechanisms and driving factors of sorption. Statistical analysis suggests that (i) partitioning was the main driver for sorption to sorbents with small specific surface area (< 25 m²/g), whereas (ii) specific mechanisms dominated sorption to sorbents with larger specific surface area. Results showed that factors usually not considered for the sorption of neutral contaminants play an important role for the sorption of organic acids. The pH dependent lipophilicity ratio (i.e. D instead of Kow), ash content and ionic strength are key factors influencing the sorption of acidic organic

  13. The impact of wafering on organic and inorganic surface contaminations

    NASA Astrophysics Data System (ADS)

    Meyer, S.; Wahl, S.; Timmel, S.; Köpge, R.; Jang, B.-Y.

    2016-08-01

    Beside the silicon feedstock material, the crystallization process and the cell processing itself, the wafer sawing process can strongly determine the final solar cell quality. Especially surface contamination is introduced in this process step because impurities from sawing meet with a virgin silicon surface which is highly reactive until the oxide layer is formed. In this paper we quantitatively analysed both, the organic and inorganic contamination on wafer surfaces and show that changes of process parameters during wafering may cause dramatic changes in surface purity. We present powerful techniques for the monitoring of wafer surface quality which is essential for the production of high efficiency and high quality solar cells.

  14. Low-cost in-soil organic contaminant sensor

    NASA Astrophysics Data System (ADS)

    Brossia, Charles E.; Wu, Samuel C.

    1991-03-01

    The First Omega Group Inc. has developed a low cost optical fiber sensing technique for detecting the presence of oils gasoline organic solvents and other oily contaminants in soils. The sensing means consists of a continuous optical fiber having a portion of its surface specially processed to render it sensitive to the presence of soil contandnants. The processed area of the fiber is positioned within the environment that is at risk of contaniination. Contact by a contaminant with the processed area of the optical fiber changes the attenuation of infrared light through the processed area in a characteristic way and in real time. The change in light attenuation is detected using a conven tional photo detector to provide indication of contamination within the soil.

  15. Reducing Organic Contamination in NASA JSC Astromaterial Curation Facility

    NASA Technical Reports Server (NTRS)

    Calaway, M. J.; Allen, C. C.; Allton, J. H.

    2013-01-01

    Future robotic and human spaceflight missions to the Moon, Mars, asteroids and comets will require handling and storing astromaterial samples with minimal inorganic and organic contamination to preserve the scientific integrity of each sample. Much was learned from the rigorous attempts to minimize and monitor organic contamination during Apollo, but it was not adequate for current analytical requirements; thus [1]. OSIRIS-REx, Hayabusa-2, and future Mars sample return will require better protocols for reducing organic contamination. Future isolation con-tainment systems for astromaterials, possibly nitrogen enriched gloveboxes, must be able to reduce organic and inorganic cross-contamination. In 2012, a baseline study established the current state of organic cleanliness in gloveboxes used by NASA JSC astromaterials curation labs that could be used as a benchmark for future mission designs [2, 3]. After standard ultra-pure water (UPW) cleaning, the majority of organic contaminates found were hydrocarbons, plasticizers, silicones, and solvents. Hydro-carbons loads (> C7) ranged from 1.9 to 11.8 ng/cm2 for TD-GC-MS wafer exposure analyses and 5.0 to 19.5 ng/L for TD-GC-MS adsorbent tube exposure. Plasticizers included < 0.6 ng/cm2 of DBP, DEP, TXIB, and DIBP. Silicones included < 0.5 ng/cm2 of cyclo(Me2SiO)x (x = 6, 8, 9, 10) and siloxane. Solvents included < 1.0 ng/cm2 of 2-cyclohexen-1-one, 3,5,5-trimethyl- (Isopho-rone), N-formylpiperidine, and 2-(2-butoxyethoxy) ethanol. In addition, DBF, rubber/polymer additive was found at < 0.2 ng/cm2 and caprolactam, nylon-6 at < 0.6 ng/cm2. Reducing Organics: The Apollo program was the last sam-ple return mission to place high-level organic requirements and biological containment protocols on a curation facility. The high vacuum complex F-201 glovebox in the Lunar Receiving Labora-tory used ethyl alcohol (190 proof), 3:1 benzene/methanol (nano grade solution), and heat sterilization at 130degC for 48 hours to reduce organic

  16. Inclusion of emerging organic contaminants in groundwater monitoring plans.

    PubMed

    Lamastra, Lucrezia; Balderacchi, Matteo; Trevisan, Marco

    2016-01-01

    Groundwater is essential for human life and its protection is a goal for the European policies. All the anthropogenic activities could impact on water quality. •Conventional pollutants and more than 700 emerging pollutants, resulting from point and diffuse source contamination, threat the aquatic ecosystem.•Policy-makers and scientists will have to cooperate to create an initial groundwater emerging pollutant priority list, to answer at consumer demands for safety and to the lack of conceptual models for emerging pollutants in groundwater.•Among the emerging contaminants and pollutants this paper focuses on organic wastewater contaminants (OWCs) mainly released into the environment by domestic households, industry, hospitals and agriculture. This paper starts from the current regulatory framework and from the literature overview to explain how the missing conceptual model for OWCs could be developed.•A full understanding of the mechanisms leading to the contamination and the evidence of the contamination must be the foundation of the conceptual model. In this paper carbamazepine, galaxolide and sulfamethozale, between the OWCs, are proposed as "environmental tracers" to identify sources and pathways ofcontamination/pollution.

  17. Inclusion of emerging organic contaminants in groundwater monitoring plans.

    PubMed

    Lamastra, Lucrezia; Balderacchi, Matteo; Trevisan, Marco

    2016-01-01

    Groundwater is essential for human life and its protection is a goal for the European policies. All the anthropogenic activities could impact on water quality. •Conventional pollutants and more than 700 emerging pollutants, resulting from point and diffuse source contamination, threat the aquatic ecosystem.•Policy-makers and scientists will have to cooperate to create an initial groundwater emerging pollutant priority list, to answer at consumer demands for safety and to the lack of conceptual models for emerging pollutants in groundwater.•Among the emerging contaminants and pollutants this paper focuses on organic wastewater contaminants (OWCs) mainly released into the environment by domestic households, industry, hospitals and agriculture. This paper starts from the current regulatory framework and from the literature overview to explain how the missing conceptual model for OWCs could be developed.•A full understanding of the mechanisms leading to the contamination and the evidence of the contamination must be the foundation of the conceptual model. In this paper carbamazepine, galaxolide and sulfamethozale, between the OWCs, are proposed as "environmental tracers" to identify sources and pathways ofcontamination/pollution. PMID:27366676

  18. Report of the Organic Contamination Science Steering Group

    NASA Technical Reports Server (NTRS)

    Mahaffy, P. R.; Beaty, D. W.; Anderson, M. S.; Aveni, G.; Bada, J. L.; Clemett, S. J.; DesMaris, D. J.; Douglas, S.; Dworkin, J. P.; Kern, R. G.

    2004-01-01

    The exploration of the possible emergence and duration of life on Mars from landed platforms requires attention to the quality of measurements that address these objectives. In particular, the potential impact of terrestrial contamination on the measurement of reduced carbon with sensitive in situ instruments must be addressed in order to reach definitive conclusions regarding the source of organic molecules. Following the recommendation of the Mars Exploration Program Analysis Group (MEPAG) at its September 2003 meeting [MEPAG, 2003], the Mars Program Office at NASA Headquarters chartered the Organic Contamination Science Steering Group (OCSSG) to address this issue. The full report of the six week study of the OCSSG can be found on the MEPAG web site [1]. The study was intended to define the contamination problem and to begin to suggest solutions that could provide direction to the engineering teams that design and produce the Mars landed systems. Requirements set by the Planetary Protection Policy in effect for any specific mission do not directly address this question of the potential interference from terrestrial contaminants during in situ measurements.

  19. Susceptibility of adherent organisms from Pseudomonas aeruginosa and Staphylococcus aureus strains isolated from burn wounds to antimicrobial agents.

    PubMed

    Trafny, E A

    1998-08-01

    To assess the bactericidal effects of ciprofloxacin, netilymicin, and polymyxin B on adherent Pseudomonas aeruginosa organisms and also the bactericidal effects of ciprofloxacin, vancomycin and teicoplanin on adherent Staphylococcus aureus cells, a simple end-point microplate assay, based on the method described by Miyake et al. was used in the present study. As results of the assay, the minimal inhibitory concentration (MICADH) values are taken, which express the susceptibility of the bacterial cells spontaneously released from the surface of adherent microcolonies to antimicrobial agents. Also, a minimal bactericidal concentration (MBCADH) value was read, which is defined as the lowest antibiotic concentration required to kill the sessile bacterial cells. For twenty P. aeruginosa strains and nineteen S. aureus strains isolated from burn wounds, an enhanced resistance against bactericidal action of the applied antibiotics was observed when bacterial cells were attached to polystyrene surface. The MICADH values were comparable with the conventional MIC values only for ciprofloxacin and netilmicin for P. aeruginosa strains. The MBCADH values exceeded many times the conventional MBC values for the majority of strains. The validity of the assay was estimated in the experiment designed to determine the concentration of ciprofloxacin that should be released topically from the collagen dressing to prevent the biomaterial from microbial colonization and allow the decontamination of the wound.

  20. Natural attenuation and enhanced bioremediation of organic contaminants in groundwater.

    PubMed

    Scow, Kate M; Hicks, Kristin A

    2005-06-01

    An area of intense scientific and practical interest is the biogeochemical and microbial processes determining the success of natural attenuation, biostimulation and/or bioaugmentation treatments for organic contaminants in groundwater. Recent studies in this area have focused on the reductive dechlorination of chlorinated solvents, the degradation of the fuel additive methyl tert-butyl ether, and the removal of long-term hydrocarbon contamination. These studies have been facilitated by the use of stable isotope analysis to demonstrate in situ bioremediation and push-pull tests, in which isotopes are injected into aquifers and then quickly retrieved and analyzed, to measure in situ activity. Molecular tools such as quantitative PCR, the detection of mRNA expression, and numerous DNA fingerprinting methods have also proved valuable, being employed to identify and sometimes quantify environmentally important organisms or changes in communities. Methods to track bacteria and tools to characterize bacterial attachment properties have also offered insight into bacterial transport in situ.

  1. Organic mercury exposure from fungicide-contaminated eggs

    SciTech Connect

    Englender, S.J.; Landrigan, P.J.; Greenwood, M.R.; Atwood, R.G.; Clarkson, T.W.; Smith, J.C.

    1980-07-01

    During a period of 50 to 55 days from early January to March 2, 1979, 14 members of an extended family in Yakima, Washington, ate eggs contaminated with organic mercury. Seed grain which had been treated with a mercurial fungicide and fed to chickens in a home flock was the source of exposure. Blood mercury levels in family members ranged from 0.9 to 20.2 ppB and correlated positively with average daily egg consumption (r = 0.92). There were no symptoms or physical signs of organic mercury intoxication. Prompt confiscation of the contaminated grain, eggs, and chicken flock terminated the exposure and may have prevented the development of serious illness.

  2. Bibliography on contaminants and solubility of organic compounds in oxygen

    NASA Technical Reports Server (NTRS)

    Ordin, P. M. (Compiler)

    1975-01-01

    A compilation of a number of document citations is presented which contains information on contaminants in oxygen. Topics covered include contaminants and solubility of organic compounds in oxygen, reaction characteristics of organic compounds with oxygen, and sampling and detection limits of impurities. Each citation in the data bank contains many items of information about the document. Some of the items are title, author, abstract, corporate source, description of figures pertinent to hazards or safety, key references, and descriptors (keywords) by which the document can be retrieved. Each citation includes an evaluation of the technical contents as to being good/excellent, acceptable, or poor. The descriptors used to define the contents of the documents and subsequently used in the computerized search operations were developed for the cryogenic fluid safety by experts in the cryogenics field.

  3. Bioremediation of metals, organic and mixed contaminants with microbial mats

    SciTech Connect

    Bender, J.

    1995-12-31

    Microbial mats are natural heterotrophic and autotrophic communities dominated by cyanobacteria (blue-green algae). They are self-organized laminated structures annealed tightly together by slimy secretions from various microbial components. The surface slime of the mats effectively immobilizes the ecosystem to a variety of substrates, thereby stabilizing the most efficient internal microbial structure. Cyanobacteria mats are generated for bioremediation applications by enriching a water surface with ensiled grass clippings. These constructed mats have been used to reduce selenate to elemental selenium, remove Pb, Cd, Cu, Zn, Co, Cr, Fe and Mn from water and to remove Pb from sediments of shallow laboratory ponds. Uranium, U{sup 238}, was removed from groundwater samples at the rate of 3.19 Mg/m{sup 2}/h. Degradation of recalcitrant organic contaminants by mats is relatively rapid under both dark and light conditions. The following contaminants have been degraded in water and/or soil media by constructed mats: TNT, chrysene, naphthalene, hexadecane, phenanthrene, PCB, TCE, pulp and paper mill wastes, and three pesticides: chlordane, carbofuran and paraquat. Radio-labeled experiments with mat-treated carbofuran, petroleum distillates, TNT, chlordane, PCB and TCE show that these compounds are mineralized by the constructed mats. Mats applied to mixed contaminant solutions (TCE + Zn and TNT + pb) sequestered the metal while mineralizing the TCE. Remediation rates of the organic and inorganic components were the same in mixed solution as they were in single application.

  4. Electrokinetic remediation of six emerging organic contaminants from soil.

    PubMed

    Guedes, Paula; Mateus, Eduardo P; Couto, Nazaré; Rodríguez, Yadira; Ribeiro, Alexandra B

    2014-12-01

    Some organic contaminants can accumulate in organisms and cause irreversible damages in biological systems through direct or indirect toxic effects. In this study the feasibility of the electrokinetic (EK) process for the remediation of 17β-oestradiol (E2), 17α-ethinyloestradiol (EE2), bisphenol A (BPA), nonylphenol (NP), octylphenol (OP) and triclosan (TCS) in soils was studied in a stationary laboratory cell. The experiments were conducted using a silty loam soil (S2) at 0, 10 and 20mA and a sandy soil (S3) at 0 and 10 mA. A pH control in the anolyte reservoir (pH>13) at 10 mA was carried out using S2, too. Photo and electrodegradation experiments were also fulfilled. Results showed that EK is a viable method for the remediation of these contaminants, both through mobilization by electroosmotic flow (EOF) and electrodegradation. As EOF is very sensible to soil pH, the control in the anolyte increased EOF rate, consequently enhancing contaminants mobilization towards the cathode end. The extent of the mobilization towards the electrode end was mainly dependent on compounds solubility and octanol-water partition coefficient. In the last 24h of experiments, BPA presented the highest mobilization rate (ca. 4 μg min(-1)) with NP not being detected in the catholyte. At the end of all experiments the percentage of contaminants that remained in the soil ranged between 17 and 50 for S2, and between 27 and 48 for S3, with no statistical differences between treatments. The mass balance performed showed that the amount of contaminant not detected in the cell is similar to the quantity that potentially may suffer photo and electrodegradation.

  5. Electrokinetic remediation of six emerging organic contaminants from soil.

    PubMed

    Guedes, Paula; Mateus, Eduardo P; Couto, Nazaré; Rodríguez, Yadira; Ribeiro, Alexandra B

    2014-12-01

    Some organic contaminants can accumulate in organisms and cause irreversible damages in biological systems through direct or indirect toxic effects. In this study the feasibility of the electrokinetic (EK) process for the remediation of 17β-oestradiol (E2), 17α-ethinyloestradiol (EE2), bisphenol A (BPA), nonylphenol (NP), octylphenol (OP) and triclosan (TCS) in soils was studied in a stationary laboratory cell. The experiments were conducted using a silty loam soil (S2) at 0, 10 and 20mA and a sandy soil (S3) at 0 and 10 mA. A pH control in the anolyte reservoir (pH>13) at 10 mA was carried out using S2, too. Photo and electrodegradation experiments were also fulfilled. Results showed that EK is a viable method for the remediation of these contaminants, both through mobilization by electroosmotic flow (EOF) and electrodegradation. As EOF is very sensible to soil pH, the control in the anolyte increased EOF rate, consequently enhancing contaminants mobilization towards the cathode end. The extent of the mobilization towards the electrode end was mainly dependent on compounds solubility and octanol-water partition coefficient. In the last 24h of experiments, BPA presented the highest mobilization rate (ca. 4 μg min(-1)) with NP not being detected in the catholyte. At the end of all experiments the percentage of contaminants that remained in the soil ranged between 17 and 50 for S2, and between 27 and 48 for S3, with no statistical differences between treatments. The mass balance performed showed that the amount of contaminant not detected in the cell is similar to the quantity that potentially may suffer photo and electrodegradation. PMID:24997283

  6. Determining Passive Sampler Partition Coefficients for Dissolved-phase Organic Contaminants

    EPA Science Inventory

    Passive samplers are used for environmental and analytical purposes to measure dissolved nonionic organic contaminants (NOCs) by absorption from a contaminated medium into a clean phase, usually in the form of a synthetic organic film. Recently developed passive sampler techniqu...

  7. EXTRACTION OF ORGANIC CONTAMINANTS FROM MARINE SEDIMENTS AND TISSUES USING MICROWAVE ENERGY

    EPA Science Inventory

    In this study, we compared microwave solvent extraction (MSE) to conventional methods for extracting organic contaminants from marine sediments and tissues with high and varying moisture content. The organic contaminants measured were polychlorinated biphenyl (PCB) congeners, chl...

  8. Modelling the fate of oxidisable organic contaminants in groundwater

    NASA Astrophysics Data System (ADS)

    Barry, D. A.; Prommer, H.; Miller, C. T.; Engesgaard, P.; Brun, A.; Zheng, C.

    Subsurface contamination by organic chemicals is a pervasive environmental problem, susceptible to remediation by natural or enhanced attenuation approaches or more highly engineered methods such as pump-and-treat, amongst others. Such remediation approaches, along with risk assessment or the pressing need to address complex scientific questions, have driven the development of integrated modelling tools that incorporate physical, biological and geochemical processes. We provide a comprehensive modelling framework, including geochemical reactions and interphase mass transfer processes such as sorption/desorption, non-aqueous phase liquid dissolution and mineral precipitatation/dissolution, all of which can be in equilibrium or kinetically controlled. This framework is used to simulate microbially mediated transformation/degradation processes and the attendant microbial population growth and decay. Solution algorithms, particularly the split-operator (SO) approach, are described, along with a brief résumé of numerical solution methods. Some of the available numerical models are described, mainly those constructed using available flow, transport and geochemical reaction packages. The general modelling framework is illustrated by pertinent examples, showing the degradation of dissolved organics by microbial activity limited by the availability of nutrients or electron acceptors (i.e., changing redox states), as well as concomitant secondary reactions. Two field-scale modelling examples are discussed, the Vejen landfill (Denmark) and an example where metal contamination is remediated by redox changes wrought by injection of a dissolved organic compound. A summary is provided of current and likely future challenges to modelling of oxidisable organics in the subsurface.

  9. Organic contaminants in isolated lakes of southern Labrador, Canada

    SciTech Connect

    Lockerbie, D.M.; Clair, T.A.

    1988-10-01

    From 1980 to 1984, the Water Quality Branch of Environment Canada studied the chemical quality of the aquatic ecosystems straddling the Labrador and Quebec border in northeastern Canada. The object of the work was to get baseline information on the aquatic resources of potential hydroelectric development sites. One result from this work was the discovery of measurable levels of organic contaminants in areas isolated from any major human activity. The purpose of this report is to describe results from the survey of the five transboundary basins and, to place the results in the perspective of other work.

  10. Studies examine contaminants: Pharmaceuticals, hormones and other organic wastewater contaminants in ground water resources

    USGS Publications Warehouse

    Barnes, Kymm K.; Kolpin, Dana W.; Furlong, Edward T.; Zaugg, Steven D.; Meyer, Michael T.; Barber, Larry B.; Focazio, Michael J.

    2005-01-01

    Ground water provides approximately 40 percent of the nation’s public water supply, and the total percentage of withdrawals for irrigation has increased from 23 percent in 1950 to 42 percent in 2000. Ground water also is a major contributor to flow in many streams and rivers in the United States and has a substantial influence on river and wetland habitats for plants and animals. Organic wastewater contaminants (OWCs) in the environment recently have been documented to be of global concern with a variety of sources and source pathways.

  11. On the reversibility of environmental contamination with persistent organic pollutants.

    PubMed

    Choi, Sung-Deuk; Wania, Frank

    2011-10-15

    An understanding of the factors that control the time trends of persistent organic pollutants (POPs) in the environment is required to evaluate the effectiveness of emission reductions and to predict future exposure. Using a regional contaminant fate model, CoZMo-POP 2, and a generic bell-shaped emission profile, we simulated time trends of hypothetical chemicals with a range of POP-like partitioning and degradation properties in different compartments of a generic warm temperate environment, with the objective of identifying the processes that may prevent the reversibility of environmental contamination with POPs after the end of primary emissions. Evaporation from soil and water can prevent complete reversibility of POP contamination of the atmosphere after the end of emissions. However, under the selected conditions, only for organic chemicals within a narrow range of volatility, that is, a logarithm of the octanol air equilibrium partition coefficient between 7 and 8, and with atmospheric degradation half-lives in excess of a few month can evaporation from environmental reservoirs sustain atmospheric levels that are within an order of magnitude of those resulting from primary emissions. HCB and α-HCH fulfill these criteria, which may explain, why their atmospheric concentrations have remained relatively high decades after their main primary emissions have been largely eliminated. Soil-to-water transfer is found responsible for the lack of reversibility of POP contamination of the aqueous environment after the end of emissions, whereas reversal of water-sediment exchange, although possible, is unlikely to contribute significantly. Differences in the reversibility of contamination in air and water suggests the possibility of changes in the relative importance of various exposure pathways after the end of primary emissions, namely an increase in the importance of the aquatic food chain relative to the agricultural one, especially if the former has a benthic

  12. Mapping organic contaminant plumes in groundwater using spontaneous potentials

    NASA Astrophysics Data System (ADS)

    Forte, Sarah

    Increased water demands have raised awareness of its importance. One of the challenges facing water resource management is dealing with contaminated groundwater; delineating, characterizing and remediating it. In the last decade, spontaneous potentials have been proposed as a method for delineating degrading organic contaminant plumes in groundwater. A hypothesis proposed that the redox potential gradient due to degradation of contaminants generated an electrical potential gradient that could be measured at the ground surface. This research was undertaken to better understand this phenomenon and find under what conditions it occurs. Spontaneous potentials are electrical potentials generated by three sources that act simultaneously: electrokinetic, thermoelectric and electrochemical sources. Over contaminant plumes electrochemical sources are those of interest. Thermoelectric sources are negligible unless in geothermal areas, but we hypothesized that electrokinetic potentials could be impacted by contaminants altering sediment surface properties. We built and calibrated a laboratory apparatus to make measurements that allowed us to calculate streaming current coupling coefficients. We tested sediment from hydrocarbon impacted sites with clean and hydrocarbon polluted groundwater and found a measurable though inconsistent effect. Moreover, numerical modelling was used to demonstrate that the impact of these changes on field measurements was negligible. Spontaneous potential surveys were conducted on two field sites with well characterized degrading hydrocarbon plumes in groundwater. We did not find a correlation between redox conditions and spontaneous potential, even after the electrical measurements were corrected for anthropogenic noise. In order to determine why the expected signal was not seen, we undertook numerical modelling based on coupled fluxes using two hypothesized types of current: redox and diffusion currents. The only scenarios that produced

  13. Determination of micro-organic contaminants in groundwater (Maribor, Slovenia).

    PubMed

    Koroša, A; Auersperger, P; Mali, N

    2016-11-15

    Micro-organic (MO) contaminants in groundwater can have adverse effects on both the environment and on human health. They enter the natural environment as a result of various processes, their presence in groundwater is the result of current anthropogenic activity and pollution loads from the past. A study on the occurrence and concentrations levels of selected contaminants in water was performed in the city of Maribor, Slovenia. A total of 56 groundwater and 4 surface water samples were collected in together four rounds in different hydrogeological periods (dry and wet seasons), and a total of 13 selected contaminants were analysed in this study. Carbamazepine, propyphenazone, caffeine, 2-methyl-2H-benzotriazole (2-MBT) and 2.4-dimethyl-2H-benzotriazole (2.4-DMBT) were determined as indicators of urban pollution, while pesticides and their metabolites (atrazine, desethylatrazine, deisopropylatrazine, terbuthylazine, desethylterbuthylazine, metolachlor, simazine, propazine) were mainly defined as indicators of crop production. All of the selected MO contaminants were detected both in the aquifer and Drava River. The most frequently detected MO compounds in groundwater were desethylatrazine (frequency of detection 98.2%; max. concentration 103.0ngL(-1)), atrazine (94.6%; 229ngL(-1)), 2.4-DMBT (92.9%; 273ngL(-1)), carbamazepine (80.4%; 88.00ngL(-1)), desethylterbuthylazine (76.8%; 7.0ngL(-1)) and simazine (76.8%; 29.6ngL(-1)), whereas propyphenazone (14.3%; 10.7ngL(-1)) was the least frequently detected. Detected MO concentrations in the study were compared with results published elsewhere around the world. Concentrations in groundwater indicate specific land use in their recharge areas. On the basis of correlations and the spatial distribution of selected MOs, groundwater origin for every sampling point was determined. Sampling sites were divided into three different groups for which indicative groundwater quality properties were defined. PMID:27395079

  14. Determination of micro-organic contaminants in groundwater (Maribor, Slovenia).

    PubMed

    Koroša, A; Auersperger, P; Mali, N

    2016-11-15

    Micro-organic (MO) contaminants in groundwater can have adverse effects on both the environment and on human health. They enter the natural environment as a result of various processes, their presence in groundwater is the result of current anthropogenic activity and pollution loads from the past. A study on the occurrence and concentrations levels of selected contaminants in water was performed in the city of Maribor, Slovenia. A total of 56 groundwater and 4 surface water samples were collected in together four rounds in different hydrogeological periods (dry and wet seasons), and a total of 13 selected contaminants were analysed in this study. Carbamazepine, propyphenazone, caffeine, 2-methyl-2H-benzotriazole (2-MBT) and 2.4-dimethyl-2H-benzotriazole (2.4-DMBT) were determined as indicators of urban pollution, while pesticides and their metabolites (atrazine, desethylatrazine, deisopropylatrazine, terbuthylazine, desethylterbuthylazine, metolachlor, simazine, propazine) were mainly defined as indicators of crop production. All of the selected MO contaminants were detected both in the aquifer and Drava River. The most frequently detected MO compounds in groundwater were desethylatrazine (frequency of detection 98.2%; max. concentration 103.0ngL(-1)), atrazine (94.6%; 229ngL(-1)), 2.4-DMBT (92.9%; 273ngL(-1)), carbamazepine (80.4%; 88.00ngL(-1)), desethylterbuthylazine (76.8%; 7.0ngL(-1)) and simazine (76.8%; 29.6ngL(-1)), whereas propyphenazone (14.3%; 10.7ngL(-1)) was the least frequently detected. Detected MO concentrations in the study were compared with results published elsewhere around the world. Concentrations in groundwater indicate specific land use in their recharge areas. On the basis of correlations and the spatial distribution of selected MOs, groundwater origin for every sampling point was determined. Sampling sites were divided into three different groups for which indicative groundwater quality properties were defined.

  15. The contamination mechanism and behavior of amide bond containing organic contaminant on PEMFC

    SciTech Connect

    Cho, Hyun -Seok; Das, Mayukhee; Wang, Heli; Dinh, Huyen N.; Van Zee, J. W.

    2015-02-03

    In this paper, a study is presented of the effects of an organic contaminant containing an amide bond (-CONH-), ε-caprolactam, on polymer electrolyte membrane fuel cells (PEMFCs). The ε-caprolactam has been detected in leachates from polyphthalamide materials that are being considered for use as balance-of-plant structural materials for PEMFCs. Contamination effects from ε-caprolactam in Nafion membranes are shown to be controlled by temperature. A possible explanation of the temperature effect is the endothermic ring-opening reaction of the amide bond (-NHCO-) of the cyclic ε-caprolactam. UV-vis and ATR-IR spectroscopy studies confirmed the presence of open ring structure of ε-caprolactam in membranes. The ECSA and kinetic current for the ORR of the Pt/C catalyst were also investigated and were observed to decrease upon contamination by the ε-caprolactam. By comparison of the CVs of ammonia and acetic acid, we confirmed the adsorption of carboxylic acid (-COOH) or carboxylate anion (-COO-) onto the surface of the Pt. In conclusion, a comparison of in situ voltage losses at 80°C and 50°C also revealed temperature effects, especially in the membrane, as a result of the dramatic increase in the HFR.

  16. The contamination mechanism and behavior of amide bond containing organic contaminant on PEMFC

    DOE PAGES

    Cho, Hyun -Seok; Das, Mayukhee; Wang, Heli; Dinh, Huyen N.; Van Zee, J. W.

    2015-02-03

    In this paper, a study is presented of the effects of an organic contaminant containing an amide bond (-CONH-), ε-caprolactam, on polymer electrolyte membrane fuel cells (PEMFCs). The ε-caprolactam has been detected in leachates from polyphthalamide materials that are being considered for use as balance-of-plant structural materials for PEMFCs. Contamination effects from ε-caprolactam in Nafion membranes are shown to be controlled by temperature. A possible explanation of the temperature effect is the endothermic ring-opening reaction of the amide bond (-NHCO-) of the cyclic ε-caprolactam. UV-vis and ATR-IR spectroscopy studies confirmed the presence of open ring structure of ε-caprolactam in membranes.more » The ECSA and kinetic current for the ORR of the Pt/C catalyst were also investigated and were observed to decrease upon contamination by the ε-caprolactam. By comparison of the CVs of ammonia and acetic acid, we confirmed the adsorption of carboxylic acid (-COOH) or carboxylate anion (-COO-) onto the surface of the Pt. In conclusion, a comparison of in situ voltage losses at 80°C and 50°C also revealed temperature effects, especially in the membrane, as a result of the dramatic increase in the HFR.« less

  17. Effects of surfactants on the desorption of organic contaminants from aquifer materials. Doctoral thesis

    SciTech Connect

    Brickell, J.L.

    1989-08-01

    The efficiency of removing organic contaminants from groundwater aquifers by the pump and treat process is adversely affected by the retardation of the contaminant's mobility due to adsorption onto aquifer material. The use of surfactants in conjunction with the pump and treat process has the potential for improving contaminant mobility by solubilizing the adsorbed contaminant.

  18. Sediments Contamination with Organic Micropollutants: Current State and Perspectives

    NASA Astrophysics Data System (ADS)

    Popenda, Agnieszka; Włodarczyk-Makuła, Maria

    2016-06-01

    This study focused on the sediment contamination with some organic micropollutants based on the monitoring data together with available literature in Poland. The following persistent organic pollutants (POPs): polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and chlorinated pesticides (CP) were characterized in sediments with respect to current legislations in force. Based on accessible data, higher PAHs, PCBs and CP concentrations were found in river sediments than in lake sediments. Especially, sediments of the Oder River and its tributary in the southern part of Poland, were highly polluted. In order to minimize the risk of the secondary pollution of surface waters, it is necessary to introduce consolidated management system with sediments proceeding. Furthermore, it is also of great importance to elaborate specific regulations concerning conditions of sediments management.

  19. Actinobacillus actinomycetemcomitans contamination of toothbrushes from patients harbouring the organism.

    PubMed

    Müller, H P; Lange, D E; Müller, R F

    1989-07-01

    The main ecological niche of Actinobacillus actinomycetemcomitans (A.a.) seems to be the periodontal pocket, but it can also be isolated from supragingival plaque, buccal and tongue mucosa, or saliva. We examined toothbrushes from 21 patients, all identified as harbouring moderate to large numbers of A.a. in subgingival plaque, for contamination with this organism. 29% of the toothbrushes presented by our patients yielded detectable numbers of A.a. Immediately after toothbrushing this figure rose to 62%, but dropped to 50% after 1 h. Numbers of isolated A.a. on toothbrushes were weakly correlated with the degree of periodontal destruction, and significantly more numbers of A.a. on toothbrushes could be detected if the organism was found on mucous membranes or in saliva. There was no association with gingival inflammation, supragingival plaque nor mean numbers of isolated subgingival A.a. PMID:2760252

  20. Decontaminating materials used in ground water sampling devices: Organic contaminants

    SciTech Connect

    Parker, L.V.; Ranney, T.A.

    2000-12-31

    In these studies, the efficiency of various decontamination protocols was tested on small pieces of materials commonly used in ground water sampling devices. Three materials, which ranged in ability to sorb organic solutes, were tested: stainless steel (SS), rigid polyvinyl chloride (PVC), and polytetrafluoroethylene (PTFE). The test pieces were exposed to two aqueous test solutions: One contained three volatile organic compounds (VOCs) and one nitroaromatic compound, and the other contained four pesticides. Also, three types of polymetic tubing were exposed to pesticide solutions. Generally, the contact times were 10 minutes and 24 hours for sorption and desorption. The contaminants were removed from the nonpermeable SS and the less-sorptive rigid PVC test pieces simply by washing with a hot detergent solution and rinsing with hot water. Additional treatment was required for the PTFE test pieces exposed to the VOCs and for the low-density polyethylene (LDPE) tubing exposed to the pesticide test solution. Solvent rinsing did not improve removal of the three VOCs form the PTFE and only marginally improved removal of the residual pesticides from the LDPE. However, a hot water and detergent wash and rinse followed by oven drying at approximately 105 C was effective for removing the VOCs from the PTFE and substantially reduced pesticide contamination from the LDPE.

  1. Trace organic chemicals contamination in ground water recharge.

    PubMed

    Díaz-Cruz, M Silvia; Barceló, Damià

    2008-06-01

    Population growth and unpredictable climate changes will pose high demands on water resources in the future. Even at present, surface water is certainly not enough to cope with the water requirement for agricultural, industrial, recreational and drinking purposes. In this context, the usage of ground water has become essential, therefore, their quality and quantity has to be carefully managed. Regarding quantity, artificial recharge can guarantee a sustainable level of ground water, whilst the strict quality control of the waters intended for recharge will minimize contamination of both the ground water and aquifer area. However, all water resources in the planet are threatened by multiple sources of contamination coming from the extended use of chemicals worldwide. In this respect, the environmental occurrence of organic micropollutants such as pesticides, pharmaceuticals, industrial chemicals and their metabolites has experienced fast growing interest. In this paper an overview of the priority and emerging organic micropollutants in the different source waters used for artificial aquifer recharge purposes and in the recovered water is presented. Besides, some considerations regarding fate and removal of such compounds are also addressed.

  2. Passive sampling methods for contaminated sediments: State of the science for organic contaminants

    PubMed Central

    Lydy, Michael J; Landrum, Peter F; Oen, Amy MP; Allinson, Mayumi; Smedes, Foppe; Harwood, Amanda D; Li, Huizhen; Maruya, Keith A; Liu, Jingfu

    2014-01-01

    This manuscript surveys the literature on passive sampler methods (PSMs) used in contaminated sediments to assess the chemical activity of organic contaminants. The chemical activity in turn dictates the reactivity and bioavailability of contaminants in sediment. Approaches to measure specific binding of compounds to sediment components, for example, amorphous carbon or specific types of reduced carbon, and the associated partition coefficients are difficult to determine, particularly for native sediment. Thus, the development of PSMs that represent the chemical activity of complex compound–sediment interactions, expressed as the freely dissolved contaminant concentration in porewater (Cfree), offer a better proxy for endpoints of concern, such as reactivity, bioaccumulation, and toxicity. Passive sampling methods have estimated Cfree using both kinetic and equilibrium operating modes and used various polymers as the sorbing phase, for example, polydimethylsiloxane, polyethylene, and polyoxymethylene in various configurations, such as sheets, coated fibers, or vials containing thin films. These PSMs have been applied in laboratory exposures and field deployments covering a variety of spatial and temporal scales. A wide range of calibration conditions exist in the literature to estimate Cfree, but consensus values have not been established. The most critical criteria are the partition coefficient between water and the polymer phase and the equilibrium status of the sampler. In addition, the PSM must not appreciably deplete Cfree in the porewater. Some of the future challenges include establishing a standard approach for PSM measurements, correcting for nonequilibrium conditions, establishing guidance for selection and implementation of PSMs, and translating and applying data collected by PSMs. Integr Environ Assess Manag 2014;10:167–178. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of

  3. The organic contamination level based on the total soil mass is not a proper index of the soil contamination intensity

    USGS Publications Warehouse

    Hung, H.-W.; Daniel, Sheng G.; Lin, T.-F.; Su, Y.; Chiou, C.T.

    2009-01-01

    Concentrations of organic contaminants in common productive soils based on the total soil mass give a misleading account of actual contamination effects. This is attributed to the fact that productive soils are essentially water-saturated, with the result that the soil uptake of organic compounds occurs principally by partition into the soil organic matter (SOM). This report illustrates that the soil contamination intensity of a compound is governed by the concentration in the SOM (Com) rather than by the concentration in whole soil (Cs). Supporting data consist of the measured levels and toxicities of many pesticides in soils of widely differing SOM contents and the related levels in in-situ crops that defy explanation by the Cs values. This SOM-based index is timely needed for evaluating the contamination effects of food crops grown in different soils and for establishing a dependable priority ranking for intended remediation of numerous contamination sites.

  4. Vertical fluxes of organic contaminants in the Ligurian Sea.

    NASA Astrophysics Data System (ADS)

    Deyme, Remi; Bouloubassi, Ioanna; Taphanel-Valt, Marie-Helene; Miquel, Juan-Carlos; Lorre, Anne; Marty, Jean-Claude; Mejanelle, Laurence

    2010-05-01

    High resolution temporal series of hydrological and biogeochemical parameters have been monitored throughout the SO-DYFAMED program, aiming at better understanding the response of the ocean to anthropic and climatic disturbance. The present contribution addresses fluxes of organic semi-volatile contaminants and of biogenic lipids associated with marine sinking particles. Sediment trap samples were collected at the DYFAMED station (Ligurian Sea, NW Mediterranean Sea) from December 2000 to July 2002, at a depth of 200m and 1000m, and with a time step of 2 to 3 weeks. Polycyclic Aromatic Hydrocarbons (PAHs) and Non-Aromatic Hydrocarbons (NAHs) were investigated to characterize the levels of contamination and the fluxes of contaminants transferred from the upper marine waters to intermediate waters. Specific lipids of phytoplankton, terrigeneous matter and faecal pellets were also determined, aiming at better understanding biogeochemical processes that may impact on pollutant transfer toward deeper marine horizons. Up to 36 PAHs were identified. The 13 parent compound levels (Σ PAH13) varied from 564 to 4156 ng.g-1, with highest concentrations corresponding to winter months. The molecular profile was dominated by low molecular weight PAHs and higher abundance of alkylated homologues over parent compounds. This characteristic, together with diagnostic molecular ratios attribute the main part of PAHs to a petrogenic origin. Aliphatic hydrocarbons were largely dominated by an UCM (Unresolved Complex Mixture), accounting for ca. 91 % of NAHs, which further confirms the dominant petrogenic origin of hydrocarbons. Fluxes of PAHs13 and NAHs varied from 0.29 to 0.422 and from 0.4 to 19.0 ?g.m2.d-1, respectively. Alike concentrations, PAH fluxes were higher than those reported in other open Mediterranean locations, revealing that the study site is under a stronger anthropogenic influence. Various inputs of contaminants at the study site may be pointed out: riverine inputs

  5. DEVELOPMENT OF A PASSIVE, IN SITU, INTEGRATIVE SAMPLER FOR HYDROPHILLIC ORGANIC CONTAMINANTS IN AQUATIC ENVIRONMENTS

    EPA Science Inventory

    Until recently, hydrophobic, bioconcentratable compounds have been the primary focus of most environmental organic contaminant investigations, There is an increasing realization that a holistic hazard assessment of complex environmental contaminant mixtures requires data on the c...

  6. Removal of Persistent Organic Contaminants by Electrochemically Activated Sulfate.

    PubMed

    Farhat, Ali; Keller, Jurg; Tait, Stephan; Radjenovic, Jelena

    2015-12-15

    Solutions of sulfate have often been used as background electrolytes in the electrochemical degradation of contaminants and have been generally considered inert even when high-oxidation-power anodes such as boron-doped diamond (BDD) were employed. This study examines the role of sulfate by comparing electro-oxidation rates for seven persistent organic contaminants at BDD anodes in sulfate and inert nitrate anolytes. Sulfate yielded electro-oxidation rates 10-15 times higher for all target contaminants compared to the rates of nitrate anolyte. This electrochemical activation of sulfate was also observed at concentrations as low as 1.6 mM, which is relevant for many wastewaters. Electrolysis of diatrizoate in the presence of specific radical quenchers (tert-butanol and methanol) had a similar effect on electro-oxidation rates, illustrating a possible role of the hydroxyl radical ((•)OH) in the anodic formation of sulfate radical (SO4(•-)) species. The addition of 0.55 mM persulfate increased the electro-oxidation rate of diatrizoate in nitrate from 0.94 to 9.97 h(-1), suggesting a nonradical activation of persulfate. Overall findings indicate the formation of strong sulfate-derived oxidant species at BDD anodes when polarized at high potentials. This may have positive implications in the electro-oxidation of wastewaters containing sulfate. For example, the energy required for the 10-fold removal of diatrizoate was decreased from 45.6 to 2.44 kWh m(-3) by switching from nitrate to sulfate anolyte.

  7. Removal of Persistent Organic Contaminants by Electrochemically Activated Sulfate.

    PubMed

    Farhat, Ali; Keller, Jurg; Tait, Stephan; Radjenovic, Jelena

    2015-12-15

    Solutions of sulfate have often been used as background electrolytes in the electrochemical degradation of contaminants and have been generally considered inert even when high-oxidation-power anodes such as boron-doped diamond (BDD) were employed. This study examines the role of sulfate by comparing electro-oxidation rates for seven persistent organic contaminants at BDD anodes in sulfate and inert nitrate anolytes. Sulfate yielded electro-oxidation rates 10-15 times higher for all target contaminants compared to the rates of nitrate anolyte. This electrochemical activation of sulfate was also observed at concentrations as low as 1.6 mM, which is relevant for many wastewaters. Electrolysis of diatrizoate in the presence of specific radical quenchers (tert-butanol and methanol) had a similar effect on electro-oxidation rates, illustrating a possible role of the hydroxyl radical ((•)OH) in the anodic formation of sulfate radical (SO4(•-)) species. The addition of 0.55 mM persulfate increased the electro-oxidation rate of diatrizoate in nitrate from 0.94 to 9.97 h(-1), suggesting a nonradical activation of persulfate. Overall findings indicate the formation of strong sulfate-derived oxidant species at BDD anodes when polarized at high potentials. This may have positive implications in the electro-oxidation of wastewaters containing sulfate. For example, the energy required for the 10-fold removal of diatrizoate was decreased from 45.6 to 2.44 kWh m(-3) by switching from nitrate to sulfate anolyte. PMID:26572594

  8. Dynamics of hydrophobic organic contaminants in the Baltic proper pelagial

    SciTech Connect

    Axelman, J.; Broman, D.; Naef, C.; Pettersen, H.

    1995-12-31

    Hydrophobic organic contaminants occur in different forms in natural water. Apart from being truly dissolved in water they partition into dissolved organic carbon (DOC) and particles of different sizes including pelagic bacteria, phytoplankton and zooplankton. The distribution between the different forms is dependent on carbon turnover rates in and transport between the different compartments and on the physical and chemical properties of the compound in focus. The water phase, the DOC-phase and two particle size fractions, 0.2--2pm and 2--20 pm representing the base of the pelagic food web, were analyzed for their content of PCBs and PAHs during summer and winter conditions in the open sea in the Baltic proper. New methods for separating truly dissolved from DOC-bound compounds have been developed using a high capacity perfusion adsorbent and large scale gas sparging. The small particle size fraction was sampled using high volume tangential flow filtration. The possibility to separate between these four different compartments has given a more detailed picture of the short term dynamics of hydrophobic organic compounds in the important base of the pelagial food web.

  9. Organic waste compounds as contaminants in Milwaukee-area streams

    USGS Publications Warehouse

    Baldwin, Austin K.; Corsi, Steven R.; Magruder, Christopher; Magruder, Matthew; Bruce, Jennifer L.

    2015-09-22

    Organic waste compounds (OWCs) are ingredients and by-products of common agricultural, industrial, and household substances that can contaminate our streams through sources like urban runoff, sewage overflows, and leaking septic systems. To better understand how OWCs are affecting Milwaukee-area streams, the U.S. Geological Survey, in cooperation with the Milwaukee Metropolitan Sewerage District, conducted a three-year study to investigate the presence and potential toxicity of 69 OWCs in base flow, stormflow, pore water, and sediment at 14 stream sites and 3 Milwaukee harbor locations. This fact sheet summarizes the major findings of this study, including detection frequencies and concentrations, potential toxicity, the prevalence of polycyclic aromatic hydrocarbons (PAHs), and the influence of urbanization.

  10. Application of passive sampling for measuring dissolved concentrations of organic contaminants in the water column at three marine superfund sites

    EPA Science Inventory

    At contaminated sediment sites, including U.S. EPA Superfund sites, it is critical to measure water column concentrations of freely dissolved contaminants to understand the complete exposure of aquatic organisms to hydrophobic organic contaminants (HOCs). However, historically a...

  11. Characterisation of organic contaminants in the CLOUD chamber at CERN

    NASA Astrophysics Data System (ADS)

    Schnitzhofer, R.; Metzger, A.; Breitenlechner, M.; Jud, W.; Heinritzi, M.; de Menezes, L.-P.; Duplissy, J.; Guida, R.; Haider, S.; Kirkby, J.; Mathot, S.; Minginette, P.; Onnela, A.; Walther, H.; Wasem, A.; Hansel, A.; The Cloud Team

    2014-07-01

    The CLOUD experiment (Cosmics Leaving OUtdoor Droplets) investigates the nucleation of new particles and how this process is influenced by galactic cosmic rays in an electropolished, stainless-steel environmental chamber at CERN (European Organization for Nuclear Research). Since volatile organic compounds (VOCs) can act as precursor gases for nucleation and growth of particles, great efforts have been made to keep their unwanted background levels as low as possible and to quantify them. In order to be able to measure a great set of VOCs simultaneously in the low parts per trillion (pptv) range, proton-transfer-reaction mass spectrometry (PTR-MS) was used. Initially the total VOC background concentration strongly correlated with ozone in the chamber and ranged from 0.1 to 7 parts per billion (ppbv). Plastic used as sealing material in the ozone generator was found to be a major VOC source. Especially oxygen-containing VOCs were generated together with ozone. These parts were replaced by stainless steel after CLOUD3, which strongly reduced the total VOC background. An additional ozone-induced VOC source is surface-assisted reactions at the electropolished stainless steel walls. The change in relative humidity (RH) from very dry to humid conditions increases background VOCs released from the chamber walls. This effect is especially pronounced when the RH is increased for the first time in a campaign. Also the dead volume of inlet tubes for trace gases that were not continuously flushed was found to be a short but strong VOC contamination source. For lower ozone levels (below 100 ppbv) the total VOC contamination was usually below 1 ppbv and therewith considerably cleaner than a comparable Teflon chamber. On average about 75% of the total VOCs come from only five exact masses (tentatively assigned as formaldehyde, acetaldehyde, acetone, formic acid, and acetic acid), which have a rather high vapour pressure and are therefore not important for nucleation and growth of

  12. A national survey of trace organic contaminants in Australian rivers.

    PubMed

    Scott, Philip D; Bartkow, Michael; Blockwell, Stephen J; Coleman, Heather M; Khan, Stuart J; Lim, Richard; McDonald, James A; Nice, Helen; Nugegoda, Dayanthi; Pettigrove, Vincent; Tremblay, Louis A; Warne, Michael St J; Leusch, Frederic D L

    2014-09-01

    Trace organic contaminant (TrOC) studies in Australia have, to date, focused on wastewater effluents, leaving a knowledge gap of their occurrence and risk in freshwater environments. This study measured 42 TrOCs including industrial compounds, pesticides, and pharmaceuticals and personal care products by liquid chromatography tandem mass spectrometry at 73 river sites across Australia quarterly for 1 yr. Trace organic contaminants were found in 92% of samples, with a median of three compounds detected per sample (maximum 18). The five most commonly detected TrOCs were the pharmaceuticals salicylic acid (82%, maximum = 1530 ng/L), paracetamol (also known as acetaminophen; 45%, maximum = 7150 ng/L), and carbamazepine (27%, maximum = 682 ng/L), caffeine (65%, maximum = 3770 ng/L), and the flame retardant (2-chloroethyl) phosphate (44%, maximum = 184 ng/L). Pesticides were detected in 28% of the samples. To determine the risk posed by the detected TrOCs to the aquatic environment, hazard quotients were calculated by dividing the maximum concentration detected for each compound by the predicted no-effect concentrations. Three of the 42 compounds monitored (the pharmaceuticals carbamazepine and sulfamethoxazole and the herbicide simazine) had a hazard quotient >1, suggesting that they may be causing adverse effects at the most polluted sites. A further 10 compounds had hazard quotients >0.1, indicating a potential risk; these included four pharmaceuticals, three personal care products, and three pesticides. Most compounds had hazard quotients significantly <0.1. The number of TrOCs measured in this study was limited and further investigations are required to fully assess the risk posed by complex mixtures of TrOCs on exposed biota. PMID:25603256

  13. Secondary environmental impacts of remedial alternatives for sediment contaminated with hydrophobic organic contaminants.

    PubMed

    Choi, Yongju; Thompson, Jay M; Lin, Diana; Cho, Yeo-Myoung; Ismail, Niveen S; Hsieh, Ching-Hong; Luthy, Richard G

    2016-03-01

    This study evaluates secondary environmental impacts of various remedial alternatives for sediment contaminated with hydrophobic organic contaminants using life cycle assessment (LCA). Three alternatives including two conventional methods, dredge-and-fill and capping, and an innovative sediment treatment technique, in-situ activated carbon (AC) amendment, are compared for secondary environmental impacts by a case study for a site at Hunters Point Shipyard, San Francisco, CA. The LCA results show that capping generates substantially smaller impacts than dredge-and-fill and in-situ amendment using coal-based virgin AC. The secondary impacts from in-situ AC amendment can be reduced effectively by using recycled or wood-based virgin AC as production of these materials causes much smaller impacts than coal-based virgin AC. The secondary environmental impacts are highly sensitive to the dredged amount and the distance to a disposal site for dredging, the capping thickness and the distance to the cap materials for capping, and the AC dose for in-situ AC amendment. Based on the analysis, this study identifies strategies to minimize secondary impacts caused by different remediation activities: optimize the dredged amount, the capping thickness, or the AC dose by extensive site assessments, obtain source materials from local sites, and use recycled or bio-based AC. PMID:26590871

  14. Degradation of recalcitrant organic contaminants by solar photocatalysis.

    PubMed

    Mansouri, L; Bousselmi, L; Ghrabi, A

    2007-01-01

    Biological pre-treated landfill leachates of Djebel Chakir contains some macromolecular organic substances that are resistant to biological degradation. The aim of the present work is to assess the feasibility of removing refractory organic pollutants in biological pre-treated landfill leachate by solar photocatalyse process. Leachate pollutant contents are studied to assess their contribution to leachate pollution and their treatability by solar photocatalyse process. Phenol is chosen as model of pollutants, to evaluate its removal and the efficiency of the photocatalytic system. The experiments were carried out in suspended photocatalytic reactor, using TiO2 Degussa P25, under sunlight illumination (UV-A: 15-31 W/cm2). Under optimum operational conditions, applied to single reactant (phenol), the system presents a TOC removal of 90% (the degradation follows a first-order kinetic). Based on the TOC removal, the results shows that the degradation of biological pre-treated leachate follows a zero-order kinetic. After 5 h of sunlight exposure, 74% of COT is removed. The TOC removal is the best without any correction of the pH and at the TiO2 concentration of 2.5 g/L. The photocatalytic degradation of organic contaminants as well as the formation and disappearance of the by-products were followed by GC/MS. The solar photocatalysis processes induce several modifications of the matrix leading to more biodegradable forms: all the remaining and new compounds generated after the biological pre-treatment of leachate are degraded and other types of organics appear, mainly carboxylic acid, aliphatic hydrocarbons and phtalic acids.

  15. Organic contaminants in bats: trends and new issues.

    PubMed

    Bayat, Sara; Geiser, Fritz; Kristiansen, Paul; Wilson, Susan C

    2014-02-01

    Exposure to contaminants, often pesticides, has been implicated as a major factor contributing to decreases in bat populations. Bats provide essential ecosystem services and a sustained, thriving population is vital for ecosystem health. Understanding issues threatening their survival is crucial for their protection and conservation. This paper provides the first review for 12years on organic pollutants in bats and aims to investigate trends and any new issues impacting bat resilience. Organochlorine (OC) pesticides have been reported most often, especially in the older literature, with the dichlorodiphenyltrichloroethane (DDT) metabolite, dichlorodiphenyldichloroethylene (DDE), present at highest concentrations in tissues analyzed. The OC pesticide concentrations reported in bat tissues have declined significantly since the late 1970s, presumably as a result of restrictions in use. For example, DDE study mean concentrations over time periods 1970-1980, 1981-1999 and 2000-2013 ranged from 2.6-62, 0.05-2.31, 0.08-0.19ppm wet weight, respectively. Exposure, however, still occurs from remaining residues, many years after the compounds have been actively used. In recent years (2000-2013), a range of other organic chemicals have been reported in bat tissues including brominated flame retardants (polybrominated diphenyl ether at a mean concentration of 2.9ppm lipid weight) and perfluorinated compounds (perfluorooctanyl sulfonate at a mean concentration 0.09ppm wet weight). The persistent organic compounds concentrate in tissues with higher fat content notably back-depot fat. Numerous factors influence exposure, residues detected and concentrations in different individuals, species and tissues which must be understood to provide meaningful assessment of the impacts of exposure. Exposure can lead to not only acute and lethal impacts, but also physiological sub-lethal and chronic effects, often linked to the annual cycle of fat deposition and withdrawal. Current challenges

  16. Rethinking adherence.

    PubMed

    Steiner, John F

    2012-10-16

    In 2012, the Centers for Medicare & Medicaid Services (CMS) will introduce measures of adherence to oral hypoglycemic, antihypertensive, and cholesterol-lowering drugs into its Medicare Advantage quality program. To meet these quality goals, delivery systems will need to develop and disseminate strategies to improve adherence. The design of adherence interventions has too often been guided by the mistaken assumptions that adherence is a single behavior that can be predicted from readily available patient characteristics and that individual clinicians alone can improve adherence at the population level.Effective interventions require recognition that adherence is a set of interacting behaviors influenced by individual, social, and environmental forces; adherence interventions must be broadly based, rather than targeted to specific population subgroups; and counseling with a trusted clinician needs to be complemented by outreach interventions and removal of structural and organizational barriers. To achieve the adherence goals set by CMS, front-line clinicians, interdisciplinary teams, organizational leaders, and policymakers will need to coordinate efforts in ways that exemplify the underlying principles of health care reform.

  17. Persistent Intraepithelial Lymphocytosis in Celiac Patients Adhering to Gluten-Free Diet Is Not Abolished Despite a Gluten Contamination Elimination Diet.

    PubMed

    Zanini, Barbara; Marullo, Monica; Villanacci, Vincenzo; Salemme, Marianna; Lanzarotto, Francesco; Ricci, Chiara; Lanzini, Alberto

    2016-01-01

    The gluten-free diet (GFD) is the only validated treatment for celiac disease (CD), but despite strict adherence, complete mucosal recovery is rarely obtained. The aim of our study was to assess whether complete restitutio ad integrum could be achieved by adopting a restrictive diet (Gluten Contamination Elimination Diet, GCED) or may depend on time of exposure to GFD. Two cohorts of CD patients, with persisting Marsh II/Grade A lesion at duodenal biopsy after 12-18 months of GFD (early control) were identified. Patients in Cohort A were re-biopsied after a three-month GCED (GCED control) and patients in Cohort B were re-biopsied after a minimum of two years on a standard GFD subsequent to early control (late control). Ten patients in Cohort A and 19 in Cohort B completed the study protocol. There was no change in the classification of duodenal biopsies in both cohorts. The number of intraepithelial lymphocytes, TCRγδ+ (T-Cell Receptor gamma delta) T cell and eosinophils significantly decreased at GCED control (Cohort A) and at late control (Cohort B), compared to early control. Duodenal intraepithelial lymphocytosis persisting in CD patients during GFD is not eliminated by a GCED and is independent of the length of GFD. [NCT 02711696]. PMID:27571100

  18. Persistent Intraepithelial Lymphocytosis in Celiac Patients Adhering to Gluten-Free Diet Is Not Abolished Despite a Gluten Contamination Elimination Diet

    PubMed Central

    Zanini, Barbara; Marullo, Monica; Villanacci, Vincenzo; Salemme, Marianna; Lanzarotto, Francesco; Ricci, Chiara; Lanzini, Alberto

    2016-01-01

    The gluten-free diet (GFD) is the only validated treatment for celiac disease (CD), but despite strict adherence, complete mucosal recovery is rarely obtained. The aim of our study was to assess whether complete restitutio ad integrum could be achieved by adopting a restrictive diet (Gluten Contamination Elimination Diet, GCED) or may depend on time of exposure to GFD. Two cohorts of CD patients, with persisting Marsh II/Grade A lesion at duodenal biopsy after 12–18 months of GFD (early control) were identified. Patients in Cohort A were re-biopsied after a three-month GCED (GCED control) and patients in Cohort B were re-biopsied after a minimum of two years on a standard GFD subsequent to early control (late control). Ten patients in Cohort A and 19 in Cohort B completed the study protocol. There was no change in the classification of duodenal biopsies in both cohorts. The number of intraepithelial lymphocytes, TCRγδ+ (T-Cell Receptor gamma delta) T cell and eosinophils significantly decreased at GCED control (Cohort A) and at late control (Cohort B), compared to early control. Duodenal intraepithelial lymphocytosis persisting in CD patients during GFD is not eliminated by a GCED and is independent of the length of GFD. [NCT 02711696] PMID:27571100

  19. Characterisation of organic contaminants in the CLOUD chamber at CERN

    NASA Astrophysics Data System (ADS)

    Schnitzhofer, R.; Metzger, A.; Breitenlechner, M.; Jud, W.; Heinritzi, M.; de Menezes, L.-P.; Duplissy, J.; Guida, R.; Haider, S.; Kirkby, J.; Mathot, S.; Minginette, P.; Onnela, A.; Walther, H.; Wasem, A.; Hansel, A.; Cloud Team

    2013-08-01

    The CLOUD experiment (Cosmics Leaving OUtdoor Droplets) investigates the nucleation of new particles and how this process is influenced by galactic cosmic rays in an electro-polished, stainless-steel environmental chamber at CERN (European Organization for Nuclear Research). Since volatile organic compounds (VOCs) can act as precursor gases for nucleation and growth of particles, great efforts have been made to keep their unwanted background levels as low as possible and to quantify them. In order to be able to measure a great set of VOCs simultaneously in the low parts per trillion (pptv) range, proton-transfer-reaction mass spectrometry (PTR-MS) was used. Initially the total VOC background concentration strongly correlated with ozone in the chamber and ranged from 0.1 to 7 parts per billion (ppbv). Plastic used as sealing material in the ozone generator was found to be a major VOC source. Especially oxygen-containing VOCs were generated together with ozone. These parts were replaced by stainless steel from CLOUD4 (June 2011) on, which strongly reduced the total VOC background. An additional ozone induced VOC source is surface assisted reactions at the electropolished stainless steel walls. The change in relative humidity (RH) from very dry to humid conditions increases background VOCs released from the chamber walls. This effect is especially pronounced when the RH is increased for the first time in a campaign. Also the dead volume of inlet tubes for trace gases that were not continuously flushed were found to be a short but strong VOC contamination source. For the later CLOUD campaigns lower ozone levels (below 100 ppbv) were used. During these conditions the total VOC contamination was usually below 1 ppbv and therewith considerably cleaner than a comparable Teflon chamber. On average more than 80% of the total VOCs are coming from only 5 exact masses (tentatively assigned as formaldehyde, acetaldehyde, acetone, formic acid, and acetic acid), which have a

  20. SALT-OVERLY SENSITIVE5 Mediates Arabidopsis Seed Coat Mucilage Adherence and Organization through Pectins1[W][OPEN

    PubMed Central

    Griffiths, Jonathan S.; Tsai, Allen Yi-Lun; Xue, Hui; Voiniciuc, Cătălin; Šola, Krešimir; Seifert, Georg J.; Mansfield, Shawn D.; Haughn, George W.

    2014-01-01

    Interactions between cell wall polymers are critical for establishing cell wall integrity and cell-cell adhesion. Here, we exploit the Arabidopsis (Arabidopsis thaliana) seed coat mucilage system to examine cell wall polymer interactions. On hydration, seeds release an adherent mucilage layer strongly attached to the seed in addition to a nonadherent layer that can be removed by gentle agitation. Rhamnogalacturonan I (RG I) is the primary component of adherent mucilage, with homogalacturonan, cellulose, and xyloglucan constituting minor components. Adherent mucilage contains rays composed of cellulose and pectin that extend above the center of each epidermal cell. CELLULOSE SYNTHASE5 (CESA5) and the arabinogalactan protein SALT-OVERLY SENSITIVE5 (SOS5) are required for mucilage adherence through unknown mechanisms. SOS5 has been suggested to mediate adherence by influencing cellulose biosynthesis. We, therefore, investigated the relationship between SOS5 and CESA5. cesa5-1 seeds show reduced cellulose, RG I, and ray size in adherent mucilage. In contrast, sos5-2 seeds have wild-type levels of cellulose but completely lack adherent RG I and rays. Thus, relative to each other, cesa5-1 has a greater effect on cellulose, whereas sos5-2 mainly affects pectin. The double mutant cesa5-1 sos5-2 has a much more severe loss of mucilage adherence, suggesting that SOS5 and CESA5 function independently. Double-mutant analyses with mutations in MUCILAGE MODIFIED2 and FLYING SAUCER1 that reduce mucilage release through pectin modification suggest that only SOS5 influences pectin-mediated adherence. Together, these findings suggest that SOS5 mediates adherence through pectins and does so independently of but in concert with cellulose synthesized by CESA5. PMID:24808103

  1. Heavy metals fractionation and organic matter mineralisation in contaminated calcareous soil amended with organic materials.

    PubMed

    Clemente, Rafael; Escolar, Angeles; Bernal, M Pilar

    2006-10-01

    Degradation of organic matter (OM) from organic amendments used in the remediation of metal contaminated soils leads to changes in soil chemical properties shortly after their addition, which may affect the soil metal distribution. The effects of two differing organic amendments on OM mineralisation and fractionation of heavy metals in a contaminated soil were investigated in an incubation experiment. The treatments were: control unamended soil, soil amended with fresh cow manure, and soil amended with a compost having a high maturity degree. The soil used was characteristic of the mining area at La Unión (Murcia, Spain) with 28% CaCO(3) and sandy-loam texture (pH 7.7; 2602 mg kg(-1)Zn; 1572 mg kg(-1)Pb). Manure and compost C-mineralisation after 56 days (24% and 3.8%, respectively) were below values reported previously for uncontaminated soils. Both amendments favoured Zn and Pb fixation, particularly the manure. Mn solubility increased at the beginning of the experiment due to a pH effect, and only Cu solubility increased through organic matter chelation in both amended soils.

  2. Modeling uptake of hydrophobic organic contaminants into polyethylene passive samplers.

    PubMed

    Thompson, Jay M; Hsieh, Ching-Hong; Luthy, Richard G

    2015-02-17

    Single-phase passive samplers are gaining acceptance as a method to measure hydrophobic organic contaminant (HOC) concentration in water. Although the relationship between the HOC concentration in water and passive sampler is linear at equilibrium, mass transfer models are needed for nonequilibrium conditions. We report measurements of organochlorine pesticide diffusion and partition coefficients with respect to polyethylene (PE), and present a Fickian approach to modeling HOC uptake by PE in aqueous systems. The model is an analytic solution to Fick's second law applied through an aqueous diffusive boundary layer and a polyethylene layer. Comparisons of the model with existing methods indicate agreement at appropriate boundary conditions. Laboratory release experiments on the organochlorine pesticides DDT, DDE, DDD, and chlordane in well-mixed slurries support the model's applicability to aqueous systems. In general, the advantage of the model is its application in the cases of well-agitated systems, low values of polyethylene-water partioning coefficients, thick polyethylene relative to the boundary layer thickness, and/or short exposure times. Another significant advantage is the ability to estimate, or at least bound, the needed exposure time to reach a desired CPE without empirical model inputs. A further finding of this work is that polyethylene diffusivity does not vary by transport direction through the sampler thickness. PMID:25607420

  3. Occurrence and fate of organic contaminants during onsite wastewater treatment

    USGS Publications Warehouse

    Conn, K.E.; Barber, L.B.; Brown, G.K.; Siegrist, R.L.

    2006-01-01

    Onsite wastewater treatment systems serve approximately 25% of the U.S. population. However, little is known regarding the occurrence and fate of organic wastewater contaminants (OWCs), including endocrine disrupting compounds, during onsite treatment. A range of OWCs including surfactant metabolites, steroids, stimulants, metal-chelating agents, disinfectants, antimicrobial agents, and pharmaceutical compounds was quantified in wastewater from 30 onsite treatment systems in Summit and Jefferson Counties, CO. The onsite systems represent a range of residential and nonresidential sources. Eighty eight percent of the 24 target compounds were detected in one or more samples, and several compounds were detected in every wastewater sampled. The wastewater matrices were complex and showed unique differences between source types due to differences in water and consumer product use. Nonresidential sources generally had more OWCs at higher concentrations than residential sources. Additional aerobic biofilter-based treatment beyond the traditional anaerobic tank-based treatment enhanced removal for many OWCs. Removal mechanisms included volatilization, biotransformation, and sorption with efficiencies from 99% depending on treatment type and physicochemical properties of the compound. Even with high removal rates during confined unit onsite treatment, OWCs are discharged to soil dispersal units at loadings up to 20 mg/m2/d, emphasizing the importance of understanding removal mechanisms and efficiencies in onsite treatment systems that discharge to the soil and water environments. ?? 2006 American Chemical Society.

  4. Analyses of organic and inorganic contaminants in Salton Sea fish.

    PubMed

    Riedel, Ralf; Schlenk, Daniel; Frank, Donnell; Costa-Pierce, Barry

    2002-05-01

    Chemical contamination of fish from the Salton Sea, a quasi-marine lake in Southern California, could adversely impact millions of birds using the Pacific Flyway and thousands of humans using the lake for recreation. Bairdiella icistia (bairdiella), Cynoscion xanthulus (orangemouth corvina), and Oreochromis spp. (tilapia) were sampled from two river mouths and two nearshore areas of the Salton Sea. Muscle tissues were analyzed for a complete suite of 14 trace metals and 53 pesticides. Fish muscle tissues had concentrations of selenium ranging between 1.89 and 2.73 microg/g wet weight. 4,4'-DDE accounted for 94% of the total DDT metabolites. Total DDTs ranged between 17.1 and 239.0 and total PCBs between 2.5 and 18.6 ng/g wet weight. PCB congeners 132, 138, 153, 168, and 180 comprised over 50% of the total PCBs. Given the potential implementation of a commercial fishing at the Salton Sea in the future, the presence of persistent organic pollutants and selenium warrants further research into the effects of these mixtures on fish populations, and on wildlife and humans consuming fish. PMID:12146823

  5. Organic contaminants in Great Lakes tributaries: Identification of watersheds and chemicals of greatest concern

    EPA Science Inventory

    Trace organic contaminant concentrations in some Great Lakes tributaries indicate potential for adverse effects on aquatic organisms. Chemicals used in agriculture, industry, and households enter surface waters via variety of sources, including urban and agricultural runoff, sewa...

  6. The role of the global cryosphere in the fate of organic contaminants

    NASA Astrophysics Data System (ADS)

    Grannas, A. M.; Bogdal, C.; Hageman, K. J.; Halsall, C.; Harner, T.; Hung, H.; Kallenborn, R.; Klán, P.; Klánová, J.; Macdonald, R. W.; Meyer, T.; Wania, F.

    2012-07-01

    The cryosphere is an important component of global organic contaminant cycles. Snow is an efficient scavenger of atmospheric organic pollutants while a seasonal snowpack, sea ice, glaciers and ice caps are contaminant reservoirs on time scales ranging from days to millennia. Important physical and chemical processes occurring in the various cryospheric compartments impact contaminant cycling and fate. A variety of interactions and feedbacks also occur within the cryospheric system, most of which are susceptible to perturbations due to climate change. In this article, we review the current state of knowledge regarding the transport and processing of organic contaminants in the global cryosphere with an emphasis on the role of a changing climate.

  7. Modeling Organic Contaminant Desorption from Municipal Solid Waste Components

    NASA Astrophysics Data System (ADS)

    Knappe, D. R.; Wu, B.; Barlaz, M. A.

    2002-12-01

    Approximately 25% of the sites on the National Priority List (NPL) of Superfund are municipal landfills that accepted hazardous waste. Unlined landfills typically result in groundwater contamination, and priority pollutants such as alkylbenzenes are often present. To select cost-effective risk management alternatives, better information on factors controlling the fate of hydrophobic organic contaminants (HOCs) in landfills is required. The objectives of this study were (1) to investigate the effects of HOC aging time, anaerobic sorbent decomposition, and leachate composition on HOC desorption rates, and (2) to simulate HOC desorption rates from polymers and biopolymer composites with suitable diffusion models. Experiments were conducted with individual components of municipal solid waste (MSW) including polyvinyl chloride (PVC), high-density polyethylene (HDPE), newsprint, office paper, and model food and yard waste (rabbit food). Each of the biopolymer composites (office paper, newsprint, rabbit food) was tested in both fresh and anaerobically decomposed form. To determine the effects of aging on alkylbenzene desorption rates, batch desorption tests were performed after sorbents were exposed to toluene for 30 and 250 days in flame-sealed ampules. Desorption tests showed that alkylbenzene desorption rates varied greatly among MSW components (PVC slowest, fresh rabbit food and newsprint fastest). Furthermore, desorption rates decreased as aging time increased. A single-parameter polymer diffusion model successfully described PVC and HDPE desorption data, but it failed to simulate desorption rate data for biopolymer composites. For biopolymer composites, a three-parameter biphasic polymer diffusion model was employed, which successfully simulated both the initial rapid and the subsequent slow desorption of toluene. Toluene desorption rates from MSW mixtures were predicted for typical MSW compositions in the years 1960 and 1997. For the older MSW mixture, which had a

  8. Layer of organic pine forest soil on top of chlorophenol-contaminated mineral soil enhances contaminant degradation.

    PubMed

    Sinkkonen, Aki; Kauppi, Sari; Simpanen, Suvi; Rantalainen, Anna-Lea; Strömmer, Rauni; Romantschuk, Martin

    2013-03-01

    Chlorophenols, like many other synthetic compounds, are persistent problem in industrial areas. These compounds are easily degraded in certain natural environments where the top soil is organic. Some studies suggest that mineral soil contaminated with organic compounds is rapidly remediated if it is mixed with organic soil. We hypothesized that organic soil with a high degradation capacity even on top of the contaminated mineral soil enhances degradation of recalcitrant chlorophenols in the mineral soil below. We first compared chlorophenol degradation in different soils by spiking pristine and pentachlorophenol-contaminated soils with 2,4,6-trichlorophenol in 10-L buckets. In other experiments, we covered contaminated mineral soil with organic pine forest soil. We also monitored in situ degradation on an old sawmill site where mineral soil was either left intact or covered with organic pine forest soil. 2,4,6-Trichlorophenol was rapidly degraded in organic pine forest soil, but the degradation was slower in other soils. If a thin layer of the pine forest humus was added on top of mineral sawmill soil, the original chlorophenol concentrations (high, ca. 70 μg g(-1), or moderate, ca. 20 μg g(-1)) in sawmill soil decreased by >40 % in 24 days. No degradation was noticed if the mineral soil was kept bare or if the covering humus soil layer was sterilized beforehand. Our results suggest that covering mineral soil with an organic soil layer is an efficient way to remediate recalcitrant chlorophenol contamination in mineral soils. The results of the field experiment are promising.

  9. Enhanced binding of hydrophobic organic contaminants by microwave-assisted humification of soil organic matter.

    PubMed

    Hur, Jin; Park, Sung-Won; Kim, Min Chan; Kim, Han S

    2013-11-01

    Enhanced binding of hydrophobic organic contaminants (HOCs) with soil organic matter (SOM) by microwave (MW) irradiation was investigated in this study. We used fluorescence excitation emission matrix, humification index (HIX), and organic carbon partitioning coefficient (Koc) to examine characteristic changes in SOM and its sorptive capacity for HOCs. When MW was irradiated to soils, protein-like fluorescence decreased but fulvic- and humic-like fluorescence increased. The addition of activated carbon in the presence of oxygen facilitated the humification-like alteration of SOM more significantly, evidenced by increases in fulvic- and humic-like fluorescence signals. The extent of SOM-phenanthrene binding also increased with MW treatment, supported by a notable increase in Koc value from 1.8×10(4) to 7.3×10(5)Lkg(-1). Various descriptors indicating the physical and chemical properties of SOM along with the relative percentage of humic-like fluorescence and HIX values demonstrated strong linear relationships with Koc values. These linear relationships indicated that the increased binding affinity of SOM for phenanthrene was attributed to enhanced SOM humification, which was stimulated by MW irradiation. Thus, our results demonstrate that MW irradiation could be effectively used for remediation or for assessing the environmental risks of HOC-contaminated soils and groundwater.

  10. ORGANIC CONTAMINANT DISTRIBUTION IN SEDIMENTS, POLYCHAETES (NEREIS VIRENS) AND THE AMERICAN LOBSTER, HOMARUS AMERICANUS IN A LABORATORY FOOD CHAIN EXPERIMENT

    EPA Science Inventory

    A laboratory experiment was conducted to investigate the transfer of organic contaminants from an environmentally contaminated marine sediment through a simple marine food chain. The infaunal polychaete, Nereis virens, was exposed to contaminated sediment collected from the Passa...

  11. The role of the global cryosphere in the fate of organic contaminants

    NASA Astrophysics Data System (ADS)

    Grannas, A. M.; Bogdal, C.; Hageman, K. J.; Halsall, C.; Harner, T.; Hung, H.; Kallenborn, R.; Klán, P.; Klánová, J.; Macdonald, R. W.; Meyer, T.; Wania, F.

    2013-03-01

    The cryosphere is an important component of global organic contaminant cycles. Snow is an efficient scavenger of atmospheric organic pollutants while a seasonal snowpack, sea ice, glaciers and ice caps are contaminant reservoirs on time scales ranging from days to millennia. Important physical and chemical processes occurring in the various cryospheric compartments impact contaminant cycling and fate. A variety of interactions and feedbacks also occur within the cryospheric system, most of which are susceptible to perturbations due to climate change. In this article, we review the current state of knowledge regarding the transport and processing of organic contaminants in the global cryosphere with an emphasis on the role of a changing climate. Given the complexity of contaminant interactions with the cryosphere and limitations on resources and research capacity, interdisciplinary research and extended collaborations are essential to close identified knowledge gaps and to improve our understanding of contaminant fate under a changing climate.

  12. Correlates of adherence and contamination in a randomized controlled trial of exercise in cancer survivors: an application of the theory of planned behavior and the five factor model of personality.

    PubMed

    Courneya, Kerry S; Friedenreich, Christine M; Sela, Rami A; Quinney, H Arthur; Rhodes, Ryan E

    2002-01-01

    In this study, we examined correlates of adherence and contamination in a randomized controlled trial (RCT) of exercise in cancer survivors using the theory of planned behavior and the Five Factor Model of personality (FFM). We randomly assigned cancer survivors in group psychotherapy classes to either a waiting-list control group (n = 45) or a home-based, moderate intensity exercise program (n = 51). At baseline, participants completed measures of the theory of planned behavior, the FFM, past exercise, physical fitness, medical variables, and demographics. We then monitored exercise over a 10-week period by weekly self-reports. Hierarchical multiple regression analyses indicated that the independent predictors of overall RCT exercise across both conditions were past exercise (beta = .36, p < .001), assignment to experimental condition (beta = .34, p < .001), sex (beta = .30, p < .001), and intention (beta = .14, p < .10). For exercise adherence in the exercise condition, the independent predictors were sex (beta = .38, p < .01), extraversion (beta = .30, p < .05), normative beliefs (beta = -.27, p < .05), and perceived behavioral control (beta = .23, p < .10). Finally, the independent predictors of exercise contamination in the control condition were past exercise (beta = .70, p < .001), sex (beta = .20, p < .05), and intention (beta = .17, p < .10). We conclude that the correlates of exercise adherence and contamination differ in kind as well as in degree. Explanations for these findings and practical implications for conducting exercise RCTs in this population are offered.

  13. Electrochemical Transformation of Trace Organic Contaminants in Latrine Wastewater.

    PubMed

    Jasper, Justin T; Shafaat, Oliver S; Hoffmann, Michael R

    2016-09-20

    Solar-powered electrochemical systems have shown promise for onsite wastewater treatment in regions where basic infrastructure for conventional wastewater treatment is not available. To assess the applicability of these systems for trace organic contaminant treatment, test compound electrolysis rate constants were measured in authentic latrine wastewater using mixed-metal oxide anodes coupled with stainless steel cathodes. Complete removal of ranitidine and cimetidine was achieved within 30 min of electrolysis at an applied potential of 3.5 V (0.7 A L(-1)). Removal of acetaminophen, ciprofloxacin, trimethoprim, propranolol, and carbamazepine (>80%) was achieved within 3 h of electrolysis. Oxidation of ranitidine, cimetidine, and ciprofloxacin was primarily attributed to reaction with NH2Cl. Transformation of trimethoprim, propranolol, and carbamazepine was attributed to direct electron transfer and to reactions with surface-bound reactive chlorine species. Relative contributions of aqueous phase ·OH, ·Cl, ·Cl2(-), HOCl/OCl(-), and Cl2 were determined to be negligible based on measured second-order reaction rate constants, probe compound reaction rates, and experiments in buffered Cl(-) solutions. Electrical energy per order of removal (EEO) increased with increasing applied potentials and current densities. Test compound removal was most efficient at elevated Cl(-) concentrations present when treated wastewater is recycled for use as flushing water (i.e., ∼ 75 mM Cl(-); EEO = 0.2-6.9 kWh log(-1) m(-3)). Identified halogenated and oxygenated electrolysis products typically underwent further transformations to unidentifiable products within the 3 h treatment cycle. Identifiable halogenated byproduct formation and accumulation was minimized during electrolysis of wastewater containing 75 mM Cl(-). PMID:27564843

  14. Electrochemical Transformation of Trace Organic Contaminants in Latrine Wastewater.

    PubMed

    Jasper, Justin T; Shafaat, Oliver S; Hoffmann, Michael R

    2016-09-20

    Solar-powered electrochemical systems have shown promise for onsite wastewater treatment in regions where basic infrastructure for conventional wastewater treatment is not available. To assess the applicability of these systems for trace organic contaminant treatment, test compound electrolysis rate constants were measured in authentic latrine wastewater using mixed-metal oxide anodes coupled with stainless steel cathodes. Complete removal of ranitidine and cimetidine was achieved within 30 min of electrolysis at an applied potential of 3.5 V (0.7 A L(-1)). Removal of acetaminophen, ciprofloxacin, trimethoprim, propranolol, and carbamazepine (>80%) was achieved within 3 h of electrolysis. Oxidation of ranitidine, cimetidine, and ciprofloxacin was primarily attributed to reaction with NH2Cl. Transformation of trimethoprim, propranolol, and carbamazepine was attributed to direct electron transfer and to reactions with surface-bound reactive chlorine species. Relative contributions of aqueous phase ·OH, ·Cl, ·Cl2(-), HOCl/OCl(-), and Cl2 were determined to be negligible based on measured second-order reaction rate constants, probe compound reaction rates, and experiments in buffered Cl(-) solutions. Electrical energy per order of removal (EEO) increased with increasing applied potentials and current densities. Test compound removal was most efficient at elevated Cl(-) concentrations present when treated wastewater is recycled for use as flushing water (i.e., ∼ 75 mM Cl(-); EEO = 0.2-6.9 kWh log(-1) m(-3)). Identified halogenated and oxygenated electrolysis products typically underwent further transformations to unidentifiable products within the 3 h treatment cycle. Identifiable halogenated byproduct formation and accumulation was minimized during electrolysis of wastewater containing 75 mM Cl(-).

  15. Hydrophobic organic contaminant transport property heterogeneity in the Borden Aquifer

    NASA Astrophysics Data System (ADS)

    Allen-King, Richelle M.; Kalinovich, Indra; Dominic, David F.; Wang, Guohui; Polmanteer, Reid; Divine, Dana

    2015-03-01

    We determined that the spatial heterogeneity in aquifer properties governing the reactive transport of volatile organic contaminants is defined by the arrangement of lithofacies. We measured permeability (k) and perchloroethene sorption distribution coefficient (Kd) for lithofacies that we delineated for samples from the Canadian Forces Base Borden Aquifer. We compiled existing data and collected 57 new cores to characterize a 30 m section of the aquifer near the test location of Mackay et al. (1986). The k and Kd were measured for samples taken at six elevations from all cores to create a data set consisting of nearly 400 colocated measurements. Through analysis of variance (corrected for multiple comparisons), we determined that the 12 originally mapped lithofacies could be grouped into five relatively distinct chemohydrofacies that capture the variability of both transport properties. The mean of ln k by lithofacies was related to the grain size and the variance was relatively consistent. In contrast, both the mean and variance of ln Kd were greater for more poorly sorted lithofacies, which were also typically more coarse-grained. Half of the aquifer sorption capacity occurred in the three highest-sorbing lithofacies but comprised only 20% of its volume. The model of the aquifer that emerged is that of discontinuous scour-fill deposits of medium sand, generally characterized by greater Kd and k, within laterally extensive fine-grained to very fine-grained sands of lower Kd and k. Our findings demonstrate the importance of considering source rock composition, transport, and deposition processes when constructing conceptual models of chemohydrofacies.

  16. LMWOA (low molecular weight organic acid) exudation by salt marsh plants: Natural variation and response to Cu contamination

    NASA Astrophysics Data System (ADS)

    Mucha, Ana P.; Almeida, C. Marisa R.; Bordalo, Adriano A.; Vasconcelos, M. Teresa S. D.

    2010-06-01

    This work aimed to evaluate, in vitro, the capability of roots of two salt marsh plants to release low molecular weight organic acids (LMWOAs) and to ascertain whether Cu contamination would stimulate or not organic acids exudation. The sea rush Juncus maritimus and the sea-club rush Scirpus maritimus, both from the lower Douro river estuary (NW Portugal), were used. Plants were collected seasonally, four times a year in 2004, during low tide. After sampling, plant roots were washed for removal of adherent particles and immersed for 2 h in a solution that matched salinity (3) and pH (7.5) of the pore water from the same location to obtain plant exudates. In one of the seasons, similar experiments were carried out but spiking the solution with different amounts of Cu in order to embrace the range between 0 and 1600 nM. In the final solutions as well as in sediment pore water LMWOAs were determined by high performance liquid chromatography. Plants were able to release, in a short period of time, relatively high amounts of LMWOAs (oxalate, citrate, malate, malonate, and succinate). In the sediment pore water oxalate, succinate and acetate were also detected. Therefore, plant roots probably contributed to the presence of some of these organic compounds in pore water. Exudation differed between the plant species and also showed some seasonally variation, particularly for S. maritimus. The release of oxalate by J. maritimus increased with Cu increase in the media. However, exudation of the other LMWOAs did not seem to be stimulated by Cu contamination in the media. This fact is compatible with the existence of alternative internal mechanisms for Cu detoxification, as denoted by the fact that in media contaminated with Cu both plant species accumulated relatively high amounts (29-83%) of the initially dissolved Cu. This study expands our knowledge on the contribution of globally dominant salt marsh plants to the release of LMWOAs into the environment.

  17. Transport of organic contaminants in subsoil horizons and effects of dissolved organic matter related to organic waste recycling practices.

    PubMed

    Chabauty, Florian; Pot, Valérie; Bourdat-Deschamps, Marjolaine; Bernet, Nathalie; Labat, Christophe; Benoit, Pierre

    2016-04-01

    Compost amendment on agricultural soil is a current practice to compensate the loss of organic matter. As a consequence, dissolved organic carbon concentration in soil leachates can be increased and potentially modify the transport of other solutes. This study aims to characterize the processes controlling the mobility of dissolved organic matter (DOM) in deep soil layers and their potential impacts on the leaching of organic contaminants (pesticides and pharmaceutical compounds) potentially present in cultivated soils receiving organic waste composts. We sampled undisturbed soil cores in the illuviated horizon (60-90 cm depth) of an Albeluvisol. Percolation experiments were made in presence and absence of DOM with two different pesticides, isoproturon and epoxiconazole, and two pharmaceutical compounds, ibuprofen and sulfamethoxazole. Two types of DOM were extracted from two different soil surface horizons: one sampled in a plot receiving a co-compost of green wastes and sewage sludge applied once every 2 years since 1998 and one sampled in an unamended plot. Results show that DOM behaved as a highly reactive solute, which was continuously generated within the soil columns during flow and increased after flow interruption. DOM significantly increased the mobility of bromide and all pollutants, but the effects differed according the hydrophobic and the ionic character of the molecules. However, no clear effects of the origin of DOM on the mobility of the different contaminants were observed.

  18. Environmental assessment of a site contaminated by organic compounds.

    PubMed

    Riccardi, C; Berardi, S; Di Basilio, M; Gariazzo, C; Giardi, P; Villarini, M

    2001-01-01

    This paper presents a study on environmental assessment of an abandoned industrial area located in central Italy. Main production was refractory materials and compounds for treatment of industrial wastewater. The present work deals with a methodology for development of a sound sampling design, chemical characterization of soil samples, definition of the degree of site contamination according to law limits and evaluation of the fate and transport of contaminants by EPA simulation model (VLEACH 2.2a). Results indicate that toxic compounds (polycyclic aromatic hydrocarbons and plasticizers) are uniformly distributed in the contaminated site and only in one sampling point their concentrations exceed law limits. Modeling results confirm that contaminants migration to groundwater can be excluded, addressing for a site remediation limited to the surface layer.

  19. Experimental increase in availability of a PAH complex organic contamination from an aged contaminated soil: consequences on biodegradation.

    PubMed

    Cébron, Aurélie; Faure, Pierre; Lorgeoux, Catherine; Ouvrard, Stéphanie; Leyval, Corinne

    2013-06-01

    Although high PAH content and detection of PAH-degraders, the PAH biodegradation is limited in aged-contaminated soils due to low PAH availability (i.e., 1%). Here, we tried to experimentally increase the soil PAH availability by keeping both soil properties and contamination composition. Organic extract was first removed and then re-incorporated in the raw soil as fresh contaminants. Though drastic, this procedure only allowed a 6-time increase in the PAH availability suggesting that the organic constituents more than ageing were responsible for low availability. In the re-contaminated soil, the mineralization rate was twice more important, the proportion of 5-6 cycles PAH was higher indicating a preferential degradation of lower molecular weight PAH. The extraction treatment induced bacterial and fungal community structures modifications, Pseudomonas and Fusarium solani species were favoured, and the relative quantity of fungi increased. In re-contaminated soil the percentage of PAH-dioxygenase gene increased, with 10 times more Gram negative representatives.

  20. Characterization of organic contaminants in porous media using nuclear magnetic resonance and spectral induced polarization measurements.

    NASA Astrophysics Data System (ADS)

    Rupert, Y. K.

    2015-12-01

    The remediation and monitoring of soils and groundwater contaminated with organic compounds is an important goal of many environmental restoration efforts. This laboratory research focuses on combining two innovative geophysical methods: nuclear magnetic resonance (NMR) and spectral induced polarization (SIP) to assess their suitability to characterize and quantify organic contaminants in porous media. Toluene, a light non-aqueous phase liquid (LNAPL), and ethoxy-nonafluorobutane, an engineered dense non-aqueous phase liquid (DNAPL), have been selected as representative organic contaminants. Low-field NMR relaxation time (T2) measurements and diffusion-relaxation (D-T2) correlation measurements, as well as low frequency SIP measurements (<10 kHz) are performed to quantify the amount of these two organic compounds in the presence of water in three types of porous media (sands, clay, and various sand-clay mixtures). The T2, D-T2, and SIP measurements are made on water, toluene, and the synthetic DNAPL in each porous media to understand the effect of different porous media on the NMR and SIP responses in each fluid. We then plan to make measurements on water-organic mixtures with varied concentrations of organic compounds in each porous medium to resolve the NMR and SIP response of the organic contaminants from that of water and to quantify the amount of organic contaminants. Building a relationship between SIP and NMR signatures from organic contaminants not only provides a fundamental yet important petrophysical relationship, but also builds a framework for continued investigation into how these two methods synergize. This will also provide spatially dense information about organic contaminated natural sediments at scales that will improve the quantitative characterization and remediation of contaminated sites.The remediation and monitoring of soils and groundwater contaminated with organic compounds is an important goal of many environmental restoration efforts

  1. EXPLORATORY ANALYSIS OF THE EFFECTS OF PARTICULATE CHARACTERISTICS ON THE VARIATION IN PARTITIONING OF NONPOLAR ORGANIC CONTAMINANTS TO MARINE SEDIMENTS

    EPA Science Inventory

    The partitioning of nonpolar organic contaminants to marine sediments is considered to be controlled by the amount of organic carbon present. However, several studies propose that other characteristics of sediments may affect the partitioning of contaminants. For this exploratory...

  2. Organic contamination analysis: High resolution mass spectrometric analysis of surface organics on selected areas of Surveyor 3

    NASA Technical Reports Server (NTRS)

    Simoneit, B. R.; Burlingame, A. L.

    1972-01-01

    The mirror and middle shroud were extracted for organics by washing the surfaces with solvents. The techniques are discussed. Ion microprobe analyses of the primarily atomic species are presented. The sources of the organic contaminants are: (1) hydrocarbons from lubricating oils and general terrestrial contamination, (2) dioctyl phthalate, probably from polyethylene bagging material (the plasticizer), (3) carboxylic acids from decomposition of grease and general terrestrial contamination, (4) silicones from sources such as lubricating oil, (5) outgassing of electronics and plasticizer, (6) vinyl alcohol and styrene copolymer, probably from electronic insulation, and (7) nitrogenous compounds from the lunar module and possibly Surveyor 3 engine exhaust.

  3. Composition and process for organic and metal contaminant fixation in soil

    DOEpatents

    Schwitzgebel, Klaus

    1994-02-08

    A method and compositions using a first ferrous iron containing solution with the iron concentration in excess of theoretical requirements to treat a contaminated site to reduce hexavalent chromium to trivalent chromium and coprecipitate trivalent chromium with other heavy metals and using a second solution of silicate containing a destabilizing salt to form a relatively impermeable gel in the contaminated site thereby fixing metals and organics to the extent that there should be no detectable ground water contamination.

  4. Milk and serum standard reference materials for monitoring organic contaminants in human samples.

    PubMed

    Schantz, Michele M; Eppe, Gauthier; Focant, Jean-François; Hamilton, Coreen; Heckert, N Alan; Heltsley, Rebecca M; Hoover, Dale; Keller, Jennifer M; Leigh, Stefan D; Patterson, Donald G; Pintar, Adam L; Sharpless, Katherine E; Sjödin, Andreas; Turner, Wayman E; Vander Pol, Stacy S; Wise, Stephen A

    2013-02-01

    Four new Standard Reference Materials (SRMs) have been developed to assist in the quality assurance of chemical contaminant measurements required for human biomonitoring studies, SRM 1953 Organic Contaminants in Non-Fortified Human Milk, SRM 1954 Organic Contaminants in Fortified Human Milk, SRM 1957 Organic Contaminants in Non-Fortified Human Serum, and SRM 1958 Organic Contaminants in Fortified Human Serum. These materials were developed as part of a collaboration between the National Institute of Standards and Technology (NIST) and the Centers for Disease Control and Prevention (CDC) with both agencies contributing data used in the certification of mass fraction values for a wide range of organic contaminants including polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, polybrominated diphenyl ether (PBDE) congeners, and polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners. The certified mass fractions of the organic contaminants in unfortified samples, SRM 1953 and SRM 1957, ranged from 12 ng/kg to 2200 ng/kg with the exception of 4,4'-DDE in SRM 1953 at 7400 ng/kg with expanded uncertainties generally <14 %. This agreement suggests that there were no significant biases existing among the multiple methods used for analysis. PMID:23132544

  5. Milk and serum standard reference materials for monitoring organic contaminants in human samples.

    PubMed

    Schantz, Michele M; Eppe, Gauthier; Focant, Jean-François; Hamilton, Coreen; Heckert, N Alan; Heltsley, Rebecca M; Hoover, Dale; Keller, Jennifer M; Leigh, Stefan D; Patterson, Donald G; Pintar, Adam L; Sharpless, Katherine E; Sjödin, Andreas; Turner, Wayman E; Vander Pol, Stacy S; Wise, Stephen A

    2013-02-01

    Four new Standard Reference Materials (SRMs) have been developed to assist in the quality assurance of chemical contaminant measurements required for human biomonitoring studies, SRM 1953 Organic Contaminants in Non-Fortified Human Milk, SRM 1954 Organic Contaminants in Fortified Human Milk, SRM 1957 Organic Contaminants in Non-Fortified Human Serum, and SRM 1958 Organic Contaminants in Fortified Human Serum. These materials were developed as part of a collaboration between the National Institute of Standards and Technology (NIST) and the Centers for Disease Control and Prevention (CDC) with both agencies contributing data used in the certification of mass fraction values for a wide range of organic contaminants including polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, polybrominated diphenyl ether (PBDE) congeners, and polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners. The certified mass fractions of the organic contaminants in unfortified samples, SRM 1953 and SRM 1957, ranged from 12 ng/kg to 2200 ng/kg with the exception of 4,4'-DDE in SRM 1953 at 7400 ng/kg with expanded uncertainties generally <14 %. This agreement suggests that there were no significant biases existing among the multiple methods used for analysis.

  6. Bioavailability and mobility of organic contaminants in soil: new three-step ecotoxicological evaluation.

    PubMed

    Prokop, Zbyněk; Nečasová, Anežka; Klánová, Jana; Čupr, Pavel

    2016-03-01

    A novel approach was developed for rapid assessment of bioavailability and potential mobility of contaminants in soil. The response of the same test organism to the organic extract, water extract and solid phase of soil was recorded and compared. This approach was designed to give an initial estimate of the total organic toxicity (response to organic extractable fraction), as well as the mobile (response to water extract) and bioavailable fraction (response to solid phase) of soil samples. Eighteen soil samples with different levels of pollution and content of organic carbon were selected to validate the novel three-step ecotoxicological evaluation approach. All samples were chemically analysed for priority contaminants, including aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH) and dichlordiphenyltrichloroethane (DDT). The ecotoxicological evaluation involved determination of toxicity of the organic, mobile and bioavailable fractions of soil to the test organism, bacterium Bacillus cereus. We found a good correlation between the chemical analysis and the toxicity of organic extract. The low toxicity of water extracts indicated low water solubility, and thus, low potential mobility of toxic contaminants present in the soil samples. The toxicity of the bioavailable fraction was significantly greater than the toxicity of water-soluble (mobile) fraction of the contaminants as deduced from comparing untreated samples and water extracts. The bioavailability of the contaminants decreased with increasing concentrations of organic carbon in evaluated soil samples. In conclusion, the three-step ecotoxicological evaluation utilised in this study can give a quick insight into soil contamination in context with bioavailability and mobility of the contaminants present. This information can be useful for hazard identification and risk assessment of soil-associated contaminants. Graphical Abstract New three-step ecotoxicological

  7. Organic Contamination Baseline Study: In NASA JSC Astromaterials Curation Laboratories. Summary Report

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.

    2013-01-01

    In preparation for OSIRIS-REx and other future sample return missions concerned with analyzing organics, we conducted an Organic Contamination Baseline Study for JSC Curation Labsoratories in FY12. For FY12 testing, organic baseline study focused only on molecular organic contamination in JSC curation gloveboxes: presumably future collections (i.e. Lunar, Mars, asteroid missions) would use isolation containment systems over only cleanrooms for primary sample storage. This decision was made due to limit historical data on curation gloveboxes, limited IR&D funds and Genesis routinely monitors organics in their ISO class 4 cleanrooms.

  8. REMOVAL OF ORGANIC CCL CONTAMINANTS FROM DRINKING WATERS BY MEMBRANE AND GAC PROCESSES

    EPA Science Inventory

    Bench-scale treatment data for membrane and granular activated carbon technologies are presented for the organic contaminants on the U.S. Environmental Protection Agency's Contaminant Candidate List (CCL). For granular activated carbon (GAC), isotherm results are presented and q...

  9. Probing Contaminant Transport to and from Clay Surfaces in Organic Solvents and Water Using Solution Calorimetry.

    PubMed

    Pourmohammadbagher, Amin; Shaw, John M

    2015-09-15

    Clays, in tailings, are a significant ongoing environmental concern in the mining and oilsands production industries, and clay rehabilitation following contamination poses challenges episodically. Understanding the fundamentals of clay behavior can lead to better environmental impact mitigation strategies. Systematic calorimetric measurements are shown to provide a framework for parsing the synergistic and antagonistic impacts of trace (i.e., parts per million level) components on the surface compositions of clays. The enthalpy of solution of as-received and "contaminated" clays, in as-received and "contaminated" organic solvents and water, at 60 °C and atmospheric pressure, provides important illustrative examples. Clay contamination included pre-saturation of clays with water and organic liquids. Solvent contamination included the addition of trace water to organic solvents and trace organic liquids to water. Enthalpy of solution outcomes are interpreted using a quantitative mass and energy balance modeling framework that isolates terms for solvent and trace contaminant sorption/desorption and surface energy effects. Underlying surface energies are shown to dominate the energetics of the solvent-clay interaction, and organic liquids as solvents or as trace contaminants are shown to displace water from as-received clay surfaces. This approach can be readily extended to include pH, salts, or other effects and is expected to provide mechanistic and quantitative insights underlying the stability of clays in tailings ponds and the behaviors of clays in diverse industrial and natural environments.

  10. Probing Contaminant Transport to and from Clay Surfaces in Organic Solvents and Water Using Solution Calorimetry.

    PubMed

    Pourmohammadbagher, Amin; Shaw, John M

    2015-09-15

    Clays, in tailings, are a significant ongoing environmental concern in the mining and oilsands production industries, and clay rehabilitation following contamination poses challenges episodically. Understanding the fundamentals of clay behavior can lead to better environmental impact mitigation strategies. Systematic calorimetric measurements are shown to provide a framework for parsing the synergistic and antagonistic impacts of trace (i.e., parts per million level) components on the surface compositions of clays. The enthalpy of solution of as-received and "contaminated" clays, in as-received and "contaminated" organic solvents and water, at 60 °C and atmospheric pressure, provides important illustrative examples. Clay contamination included pre-saturation of clays with water and organic liquids. Solvent contamination included the addition of trace water to organic solvents and trace organic liquids to water. Enthalpy of solution outcomes are interpreted using a quantitative mass and energy balance modeling framework that isolates terms for solvent and trace contaminant sorption/desorption and surface energy effects. Underlying surface energies are shown to dominate the energetics of the solvent-clay interaction, and organic liquids as solvents or as trace contaminants are shown to displace water from as-received clay surfaces. This approach can be readily extended to include pH, salts, or other effects and is expected to provide mechanistic and quantitative insights underlying the stability of clays in tailings ponds and the behaviors of clays in diverse industrial and natural environments. PMID:26296102

  11. DISTRIBUTION OF ORGANIC WASTEWATER CONTAMINANTS BETWEEN WATER AND SEDIMENT IN SURFACE WATERS OF THE UNITED STATES

    EPA Science Inventory

    Trace concentrations of pharmaceuticals and other organic wastewater contaminants have been determined in the surface waters of Europe and the United States. A preliminary report of substantially higher concentrations of pharmaceuticals in sediment suggests that bottom sediment ...

  12. Spatiotemporal characteristics of organic contaminant concentrations and ecological risk assessment in the Songhua River, China

    EPA Science Inventory

    To control source pollution and improve water quality, an understanding of the spatiotemporal characteristics of organic contaminant concentrations in affected receiving waters is necessary. The Songhua River in northeast China is the country's third-largest domestic river and lo...

  13. DEMONSTRATION BULLETIN: SOLIDIFICATION/STABILIZATION OF ORGANIC/INORGANIC CONTAMINANTS - SILICATE TECHNOLOGY CORPORATION

    EPA Science Inventory

    Silicate Technology Corporation's (STC's) technology for treating hazardous waste utilizes silicate compounds to stabilize organic and inorganic constituents in contaminated soils and sludges. STC has developed two groups of reagents: SOILSORB HM for treating wastes with inorgan...

  14. Use of Passive Samplers to Measure Dissolved Organic Contaminants in a Temperate Estuary

    EPA Science Inventory

    Measuring dissolved concentrations of organic contaminants can be challenging given their low solubilities and high particle association. However, to perform accurate risk assessments of these chemicals, knowing the dissolved concentration is critical since it is considered to b...

  15. Comparison of Passive Samplers for Monitoring Dissolved Organic Contaminants in Water Column Deployments

    EPA Science Inventory

    Nonionic organic contaminants (NOCs) are difficult to measure in the water column due to their inherent chemical properties resulting in low water solubility and high particle activity. Traditional sampling methods require large quantities of water to be extracted and interferen...

  16. Contrasting time trends of organic contaminants in Antarctic pelagic and benthic food webs.

    PubMed

    van den Brink, Nico W; Riddle, Martin J; van den Heuvel-Greve, Martine; van Franeker, Jan Andries

    2011-01-01

    We demonstrate that pelagic Antarctic seabirds show significant decreases in concentrations of some persistent organic pollutants. Trends in Adélie penguins and Southern fulmars fit in a general pattern revealed by a broad literature review. Downward trends are also visible in pelagic fish, contrasting sharply with steady or increasing concentrations in Antarctic benthic organisms. Transfer of contaminants between Antarctic pelagic and benthic food webs is associated with seasonal sea-ice dynamics which may influence the balance between the final receptors of contaminants under different climatic conditions. This complicates the predictability of future trends of emerging compounds in the Antarctic ecosystem, such as of the brominated compounds that we detected in Antarctic petrels. The discrepancy in trends between pelagic and benthic organisms shows that Antarctic biota are still final receptors of globally released organic contaminants and it remains questionable whether the total environmental burden of contaminants in the Antarctic ecosystem is declining.

  17. Assessing Organic Contaminant Fluxes from Contaminated Sediments Following Dam Removal in an Urbanized River

    EPA Science Inventory

    In this study, methods and approaches were developed and tested to assess changes in contaminant fluxes resulting from dam removal in a riverine system. Sediment traps and passive samplers were deployed to measure particulate and dissolved PAHs and PCBs in the water column prior...

  18. Organic contaminant transport and fate in the subsurface: Evolution of knowledge and understanding

    NASA Astrophysics Data System (ADS)

    Essaid, Hedeff I.; Bekins, Barbara A.; Cozzarelli, Isabelle M.

    2015-07-01

    Toxic organic contaminants may enter the subsurface as slightly soluble and volatile nonaqueous phase liquids (NAPLs) or as dissolved solutes resulting in contaminant plumes emanating from the source zone. A large body of research published in Water Resources Research has been devoted to characterizing and understanding processes controlling the transport and fate of these organic contaminants and the effectiveness of natural attenuation, bioremediation, and other remedial technologies. These contributions include studies of NAPL flow, entrapment, and interphase mass transfer that have advanced from the analysis of simple systems with uniform properties and equilibrium contaminant phase partitioning to complex systems with pore-scale and macroscale heterogeneity and rate-limited interphase mass transfer. Understanding of the fate of dissolved organic plumes has advanced from when biodegradation was thought to require oxygen to recognition of the importance of anaerobic biodegradation, multiple redox zones, microbial enzyme kinetics, and mixing of organic contaminants and electron acceptors at plume fringes. Challenges remain in understanding the impacts of physical, chemical, biological, and hydrogeological heterogeneity, pore-scale interactions, and mixing on the fate of organic contaminants. Further effort is needed to successfully incorporate these processes into field-scale predictions of transport and fate. Regulations have greatly reduced the frequency of new point-source contamination problems; however, remediation at many legacy plumes remains challenging. A number of fields of current relevance are benefiting from research advances from point-source contaminant research. These include geologic carbon sequestration, nonpoint-source contamination, aquifer storage and recovery, the fate of contaminants from oil and gas development, and enhanced bioremediation.

  19. Organic contaminant transport and fate in the subsurface: evolution of knowledge and understanding

    USGS Publications Warehouse

    Essaid, Hedeff I.; Bekins, Barbara A.; Cozzarelli, Isabelle M.

    2015-01-01

    Toxic organic contaminants may enter the subsurface as slightly soluble and volatile nonaqueous phase liquids (NAPLs) or as dissolved solutes resulting in contaminant plumes emanating from the source zone. A large body of research published in Water Resources Research has been devoted to characterizing and understanding processes controlling the transport and fate of these organic contaminants and the effectiveness of natural attenuation, bioremediation, and other remedial technologies. These contributions include studies of NAPL flow, entrapment, and interphase mass transfer that have advanced from the analysis of simple systems with uniform properties and equilibrium contaminant phase partitioning to complex systems with pore-scale and macroscale heterogeneity and rate-limited interphase mass transfer. Understanding of the fate of dissolved organic plumes has advanced from when biodegradation was thought to require oxygen to recognition of the importance of anaerobic biodegradation, multiple redox zones, microbial enzyme kinetics, and mixing of organic contaminants and electron acceptors at plume fringes. Challenges remain in understanding the impacts of physical, chemical, biological, and hydrogeological heterogeneity, pore-scale interactions, and mixing on the fate of organic contaminants. Further effort is needed to successfully incorporate these processes into field-scale predictions of transport and fate. Regulations have greatly reduced the frequency of new point-source contamination problems; however, remediation at many legacy plumes remains challenging. A number of fields of current relevance are benefiting from research advances from point-source contaminant research. These include geologic carbon sequestration, nonpoint-source contamination, aquifer storage and recovery, the fate of contaminants from oil and gas development, and enhanced bioremediation.

  20. Organic and inorganic diffuse contamination in urban soils: the case of Torino (Italy).

    PubMed

    Biasioli, Mattia; Ajmone-Marsan, Franco

    2007-08-01

    Soils in urban parks are useful tracers of diffuse contamination and could represent a potential health risk for citizens. Soils in the parks of Torino, Italy, were sampled and analysed for a broad range of organic and inorganic contaminants. Concentrations of potentially toxic elements, PAHs, PCBs and polychlorinated dibenzo-p-dioxins and dibenzofurans were often above national legislation limits, and higher than surrounding rural areas or than other cities. Mean concentrations were 233 mg kg(-1) for Cr, 164 mg kg(-1) for Ni, 124 mg kg(-1) for Pb and 170 mg kg(-1) for Zn. Other inorganic contaminants such as Cd, As, and Hg showed high concentrations in some soils. Organic contaminants were also found to be enriched in the sampled parks (e.g. maximum concentrations of PCDDs/DFs and PCBs were 12.6 ng kg(-1) and 0.310 mg kg(-1), respectively). Data from this study reveal an important enrichment of parks for some contaminants, reflecting the intensity of phenomena of diffuse contamination. Historical parks presented the highest degree of contamination, suggesting that the age of soils rather than their proximity to sources of emissions is a key factor in determining soil contamination. Data obtained in this study could be of help in the investigation and remediation practices of urban contaminated sites within large cities.

  1. The development of a sub-surface monitoring system for organic contamination in soils and groundwater.

    PubMed

    Huntley, Sharon L; Ritchie, Lawrence J; Setford, Steven J; Saini, Selwayan

    2002-04-24

    A major problem when dealing with environmental contamination is the early detection and subsequent surveillance of the contamination. This paper describes the potential of sub-surface sensor technology for the early detection of organic contaminants in contaminated soils, sediments, and landfill sites. Rugged, low-power hydrocarbon sensors have been developed, along with a data-logging system, for the early detection of phase hydrocarbons in soil. Through laboratory-based evaluation, the ability of this system to monitor organic contamination in water-based systems is being evaluated. When used in conjunction with specific immunoassays, this can provide a sensitive and low-cost solution for long-term monitoring and analysis, applicable to a wide range of field applications.

  2. Anthropogenic organic contaminants in water, sediments and benthic organisms of the mangrove-fringed Segara Anakan Lagoon, Java, Indonesia.

    PubMed

    Dsikowitzky, Larissa; Nordhaus, Inga; Jennerjahn, Tim C; Khrycheva, Polina; Sivatharshan, Yoganathan; Yuwono, Edy; Schwarzbauer, Jan

    2011-04-01

    Segara Anakan, a mangrove-fringed coastal lagoon in Indonesia, has a high diversity of macrobenthic invertebrates and is increasingly affected by human activities. We found > 50 organic contaminants in water, sediment and macrobenthic invertebrates from the lagoon most of which were polycyclic aromatic compounds (PACs). Composition of PACs pointed to petrogenic contamination in the eastern lagoon. PACs mainly consisted of alkylated PAHs, which are more abundant in crude oil than parent PAHs. Highest total PAC concentration in sediment was above reported toxicity thresholds for aquatic invertebrates. Other identified compounds derived from municipal sewage and also included novel contaminants like triphenylphosphine oxide. Numbers of stored contaminants varied between species which is probably related to differences in microhabitat and feeding mode. Most contaminants were detected in Telescopium telescopium and Polymesoda erosa. Our findings suggest that more attention should be paid to the risk potential of alkylated PAHs, which has hardly been addressed previously. PMID:21414637

  3. Anthropogenic organic contaminants in water, sediments and benthic organisms of the mangrove-fringed Segara Anakan Lagoon, Java, Indonesia.

    PubMed

    Dsikowitzky, Larissa; Nordhaus, Inga; Jennerjahn, Tim C; Khrycheva, Polina; Sivatharshan, Yoganathan; Yuwono, Edy; Schwarzbauer, Jan

    2011-04-01

    Segara Anakan, a mangrove-fringed coastal lagoon in Indonesia, has a high diversity of macrobenthic invertebrates and is increasingly affected by human activities. We found > 50 organic contaminants in water, sediment and macrobenthic invertebrates from the lagoon most of which were polycyclic aromatic compounds (PACs). Composition of PACs pointed to petrogenic contamination in the eastern lagoon. PACs mainly consisted of alkylated PAHs, which are more abundant in crude oil than parent PAHs. Highest total PAC concentration in sediment was above reported toxicity thresholds for aquatic invertebrates. Other identified compounds derived from municipal sewage and also included novel contaminants like triphenylphosphine oxide. Numbers of stored contaminants varied between species which is probably related to differences in microhabitat and feeding mode. Most contaminants were detected in Telescopium telescopium and Polymesoda erosa. Our findings suggest that more attention should be paid to the risk potential of alkylated PAHs, which has hardly been addressed previously.

  4. Erace--an integrated system for treating organic-contaminated sites

    SciTech Connect

    Caley, S.M.; Heath, W.O.; Bergsman, T.M.; Gauglitz, P.A.; Pillay, C.; Moss, R.W.; Shah, R.R.; Goheen, S.C.; Camiaoni, D.M.

    1994-11-01

    The U.S. Department of Energy`s (DOE) Pacific Northwest Laboratory (PNL) is developing a suite of electrical technologies for treating sites contaminated with hazardous organic compounds. These include: (1) Six-Phase Soil Heating (SPSH) to remove volatile and semi-volatile organic compounds from soils; (2) In Situ Corona (ISC) to decompose nonvolatile and bound organic contaminants in soils; (3) High-Energy Corona (HEC) to treat contaminated off-gases; and (4) Liquid Corona (LC) to treat contaminated liquids. These four technologies comprise ERACE (Electrical Remediation at Contaminated Environments), an integrated system for accomplishing site remediation with little or no secondary wastes produced that would require off-site treatment or disposal. Each ERACE technology can be employed individually as a stand-alone treatment process, or combined as a system for total site remediation. For example, an ERACE system for treating sites contaminated with volatile organics would integrate SPSH to remove the contaminants from the soil, LC to continuously treat an aqueous stream condensed out of the soil off-gas, and HEC to treat non-condensibles remaining in the off-gas, before atmospheric release.

  5. [Organic contaminants in the Jakusevec landfill and their impact on groundwater quality].

    PubMed

    Ahel, Marijan; Terzić, Senka; Tepić, Natasa

    2006-09-01

    Landfilling is probably, the most popular disposal method for the management of domestic and industrial waste. Unfortunately, many landfills around the world do not include leachate collection systems and present a considerable risk to the underlying aquifers. There have been numerous reports on groundwater contamination in the vicinity of unprotected landfills, paying particular attention to specific organic contaminants. This problem is especially pronounced in landfills which, in addition to ordinary domestic refuse, contain waste of industrial origin. Jakusevec, the main landfill of the city of Zagreb, belongs to this category. The recently completed remediation programme for Jakusevec included comprehensive investigations with the aim to quantify various organic contaminants in solid waste and establish their possible infiltration into the underlying soils and groundwater. A detailed analyses using chromatographic and mass spectrometric techniques made it possible to identify a number of contaminants. According to their origin, the identified compound classes can be divided into the two main categories: markers of biological waste and its microbial transformation and markers of anthropogenic waste. Our investigations have shown that the composition of organic contaminants changes dramatically during the vertical transport from the solid waste through the unsaturated zone of soil to aquifer sediments, which involves both physicochemical and biotransformation processes. The vertical transport of polar organic contaminants was very efficient and led to a significant contamination of the aquifer in the vicinity of the landfill.

  6. A partition-limited model for the plant uptake of organic contaminants from soil and water

    USGS Publications Warehouse

    Chiou, C.T.; Sheng, G.; Manes, M.

    2001-01-01

    In dealing with the passive transport of organic contaminants from soils to plants (including crops), a partition-limited model is proposed in which (i) the maximum (equilibrium) concentration of a contaminant in any location in the plant is determined by partition equilibrium with its concentration in the soil interstitial water, which in turn is determined essentially by the concentration in the soil organic matter (SOM) and (ii) the extent of approach to partition equilibrium, as measured by the ratio of the contaminant concentrations in plant water and soil interstitial water, ??pt (??? 1), depends on the transport rate of the contaminant in soil water into the plant and the volume of soil water solution that is required for the plant contaminant level to reach equilibrium with the external soil-water phase. Through reasonable estimates of plant organic-water compositions and of contaminant partition coefficients with various plant components, the model accounts for calculated values of ??pt in several published crop-contamination studies, including near-equilibrium values (i.e., ??pt ??? 1) for relatively water-soluble contaminants and lower values for much less soluble contaminants; the differences are attributed to the much higher partition coefficients of the less soluble compounds between plant lipids and plant water, which necessitates much larger volumes of the plant water transport for achieving the equilibrium capacities. The model analysis indicates that for plants with high water contents the plant-water phase acts as the major reservoir for highly water-soluble contaminants. By contrast, the lipid in a plant, even at small amounts, is usually the major reservoir for highly water-insoluble contaminants.

  7. Endophytes and their Potential to Deal with Co-contamination of Organic Contaminants (Toluene) and Toxic Metals (Nickel) during Phytoremediation

    SciTech Connect

    Weyens, N.; van der Lelie, D.; Truyens, S.; Saenen, E.; Boulet, J.; Dupae, J.; Taghavi, S.; Carleer, R.; Vangronsveld, J.

    2011-01-15

    The aim was to investigate if engineered endophytes that are capable of degrading organic contaminants, and deal with or ideally improve uptake and translocation of toxic metals, can improve phytoremediation of mixed organic-metal pollution. As a model system, yellow lupine was inoculated with the endophyte Burkholderia cepacia VM1468 possessing (a) the pTOM-Bu61 plasmid, coding for constitutive toluene/TCE degradation, and (b) the chromosomally inserted ncc-nre Ni resistance/sequestration system. As controls, plants were inoculated with B. vietnamiensis BU61 (pTOM-Bu61) and B. cepacia BU72 (containing the ncc-nre Ni resistance/sequestration system). Plants were exposed to mixes of toluene and Ni. Only inoculation with B. cepacia VM1468 resulted in decreased Ni and toluene phytotoxicity, as measured by a protective effect on plant growth and decreased activities of enzymes involved in antioxidative defence (catalase, guaiacol peroxidase, superoxide dismutase) in the roots. Besides, plants inoculated with B. cepacia VM1468 and B. vietnamiensis BU61 released less toluene through the leaves than non-inoculated plants and those inoculated with B. cepacia BU72. Ni-uptake in roots was slightly increased for B. cepacia BU72 inoculated plants. These results indicate that engineered endophytes have the potential to assist their host plant to deal with co-contamination of toxic metals and organic contaminants during phytoremediation.

  8. Toxic contaminant characterization of aquatic organisms in Galveston Bay: A pilot study. Final report

    SciTech Connect

    Brooks, J.M.; Wade, T.L.; Dennicutt, M.C.; Wiesenburg, D.A.; Wilkinson, D.

    1992-06-01

    The study characterizes contamination in edible fish and shellfish from Galveston Bay. The sampling design called for the analysis of trace contaminants in five species from four sites in Galveston Bay. The goal of the sampling program was to collect ten specimens of each target organism that were of legal market size from each collection site. Standard fisheries data were recorded for all collections. The analytical program called for the analyses of 10 individual specimens of the target organisms from each site (200 edible tissue (muscle) samples). Fifty (50) liver samples were composed for analysis from the 120 fishes. The trace contaminants that were measured included heavy metals, polynuclear aromatic hydrocarbons (PAH's), pesticides and PCBs and a GC-MS scan for other EPA organic priority pollutants. In general, trace contaminants were higher in oyster and crab tissues than fish tissue.

  9. Assessing organic contaminant fluxes from contaminated sediments following dam removal in an urbanized river.

    PubMed

    Cantwell, Mark G; Perron, Monique M; Sullivan, Julia C; Katz, David R; Burgess, Robert M; King, John

    2014-08-01

    In this study, methods and approaches were developed and tested to assess changes in contaminant fluxes resulting from dam removal in a riverine system. Sediment traps and passive samplers were deployed to measure particulate and dissolved polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the water column prior to and following removal of a small, low-head dam in the Pawtuxet River, an urbanized river located in Cranston, RI, USA. During the study, concentrations of particulate and dissolved PAHs ranged from 21.5 to 103 μg/g and from 68 to 164 ng/L, respectively. Overall, temporal trends of PAHs showed no increases in either dissolved or particulate phases following removal of the dam. Dissolved concentrations of PCBs were very low, remaining below 1.72 ng/L at all sites. Particulate PCB concentrations across sites and time showed slightly greater variability, ranging from 80 to 469 ng/g, but with no indication that dam removal influenced any increases. Particulate PAHs and PCBs were sampled continuously at the site located below the dam and did not show sustained increases in concentration resulting from dam removal. The employment of passive sampling technology and sediment traps was highly effective in monitoring the concentrations and flux of contaminants moving through the river system. Variations in river flow had no effect on the concentration of contaminants in the dissolved or particulate phases, but did influence the flux rate of contaminants exiting the river. Overall, dam removal did not cause measurable sediment disturbance or increase the concentration or fluxes of dissolved or particulate PAHs and PCBs. This is due in large part to low volumes of impounded sediment residing above the dam and highly armored sediments in the river channel, which limited erosion. Results from this study will be used to improve methods and approaches that assess the short- and long-term impacts ecological restoration activities such as

  10. Development and testing of biosensors that quantitatively and specifically detect organic contaminants

    SciTech Connect

    Jackson, P.; Keim, P.; Kuske, C.; Willardson, B.

    1996-07-01

    This is the final report of a two-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project sought to develop a more sensitive and less expensive method of detecting organic contaminants. Assaying complex environmental samples for organic contaminant content is costly and labor intensive. This often limits extensive testing. Sensitive microbial biosensors that detect specific organic contaminants in complex waste mixtures without prior separation from other waste components have been developed. Some soil microbes degrade organic compounds that contaminate the environment. These bacteria sense minute quantities of particular organic compounds then respond by activating genes encoding enzymes that degrade these molecules. Genetic manipulation of these gene regulatory processes has been employed to develop unique biosensors that detect specific organic compounds using standard biochemical assays. Such biosensors allow rapid, sensitive testing of environmental samples for selected organic contaminants. The cost of biosensor assays is at least 100-fold less than present methods, allowing more rapid and extensive testing and site characterization.

  11. Impact of mineral micropores on transport and fate of organic contaminants: a review.

    PubMed

    Cheng, Hefa; Hu, Erdan; Hu, Yuanan

    2012-03-15

    Nanometer-scale pores are abundant in porous geological media (soils, sediments, and aquifer materials), and may account for over >90% of total mineral surface areas. Sorption of organic contaminants in mineral micropores (<2 nm) plays a key role in controlling their fate and transport when the porous geological media have very low organic carbon contents (<0.1%). Significant adsorption of hydrophobic organic contaminants could only occur in the hydrophobic micropore spaces because of the strong competition from water. The rate of desorption from micropores is very slow due to hindered diffusion, resulting in distinct two-stage desorption behavior for microporous solids. Size exclusion effect prevents micropore-sorbed contaminants from being accessed by microorganisms and their extracellular enzymes, thus reducing their bioavailability and biodegradation rates. Results from recent studies indicate that sorption in micropores can also inhibit abiotic degradation of reactive contaminants by protecting them in confined spaces with little reactive water, slowing down hydrolysis and other water-mediated transformations. As a result of the inhibitory effect on abiotic and biotic transformations, and the slow desorption due to hindered diffusion, sorption in hydrophobic micropores of porous geological media can cause preservation of anthropogenic organic contaminants in the subsurface and may increase their persistence to the time scale of geological ages under appropriate conditions. From a practical perspective, understanding the role of mineral micropores is important in assessing the long-term ecotoxicological risk of organic contaminants in the subsurface and designing remediation strategies.

  12. Plasmodium chabaudi-Infected Erythrocytes Adhere to CD36 and Bind to Microvascular Endothelial Cells in an Organ-Specific Way

    PubMed Central

    Mota, Maria M.; Jarra, William; Hirst, Elizabeth; Patnaik, Pradeep K.; Holder, Anthony A.

    2000-01-01

    Adherence of erythrocytes infected with Plasmodium falciparum to microvascular endothelial cells (sequestration) is considered to play an important role in parasite virulence and pathogenesis. However, the real importance of sequestration for infection and disease has never been fully assessed. The absence of an appropriate in vivo model for sequestration has been a major barrier. We have examined the rodent malaria parasite Plasmodium chabaudi chabaudi AS in mice as a potential model. Erythrocytes infected with this parasite adhere in vitro to purified CD36, a critical endothelium receptor for binding P. falciparum-infected erythrocytes. P. c. chabaudi-infected erythrocytes adhere in vitro to endothelial cells in a gamma interferon-dependent manner, suggesting the involvement of additional adhesion molecules in the binding process, as is also the case with P. falciparum-infected cells. Furthermore, plasma or sera from infected and hyperimmune mice, respectively, have the ability to block binding of infected erythrocytes to endothelial cells. In vivo, erythrocytes containing mature P. c. chabaudi parasites are sequestered from the peripheral circulation. Sequestration is organ specific, occurring primarily in the liver, although intimate contact between infected erythrocytes and endothelial cells is also observed in the spleen and brain. The results are discussed in the context of the use of this model to study (i) the relationship between endothelial cell activation and the level of sequestration and (ii) the primary function of sequestration in malaria infection. PMID:10858230

  13. Remediation of Urban River Water by Pontederia Cordata Combined with Artificial Aeration: Organic Matter and Nutrients Removal and Root-Adhered Bacterial Communities.

    PubMed

    Gu, Dungang; Xu, Huan; He, Yan; Zhao, Feng; Huang, Minsheng

    2015-01-01

    Macrophyte combined with artificial aeration is a promising in situ remediation approach for urban rivers polluted with nutrients and organic matter. However, seasonal variations and aeration effects on phytoremediation performance and root-adhered microbial communities are still unclear. In this study, Pontederia cordata was used to treat polluted urban river water under various aeration intensities. Results showed that the highest removal efficiencies of chemical oxygen demand (COD(Cr)) and total nitrogen (TN) were attained under aeration of 30 L min(-1) in spring and summer and 15 L min(-1) in autumn, while total phosphorus (TP) removal reached maximum with aeration of 15 L min(-1) in all seasons. Moderate aeration was beneficial for increasing the diversity of root-adhered bacteria communities, and the shift of bacterial community structure was more pronounced in spring and autumn with varying aeration intensity. The dual effect, i.e. turbulence and dissolved oxygen (DO), of aeration on the removal of COD(Cr) and TN prevailed over the individual effect of DO, while DO was the most influential factor for TP removal and the root-adhered bacterial community diversity. P. cordata combined with 15 L min(-1) aeration was deemed to be the best condition tested in this study.

  14. ORGANIC WASTE CONTAMINATION INDICATORS IN SMALL GEORGIA PIEDMONT STREAMS

    EPA Science Inventory

    We monitored concentrations of dissolved organic carbon(DOC) and dissolved oxygen (DO), and other parameters in 17 small streams of the South Fork Broad River watershed on a monthly basis for 15 months. Here we present estimates of the amounts of organic waste input to these wate...

  15. HIV Medication Adherence

    MedlinePlus

    HIV Treatment HIV Medication Adherence (Last updated 3/1/2016; last reviewed 3/1/2016) Key Points Medication adherence means sticking ... exactly as prescribed. Why is adherence to an HIV regimen important? Adherence to an HIV regimen gives ...

  16. SUPERFUND TREATABILITY CLEARINGHOUSE: COMPOSITING EXPLOSIVES/ORGANICS CONTAMINATED SOILS

    EPA Science Inventory

    Laboratory scale and pilot scale studies were conducted to evaluate composting to treat sediments and soils containing explosive and organic compounds. Sediment and soil from lagoons at Army ammunition plants, located in Louisiana, Wisconsin and Pennsylvania contained high...

  17. SPECIATION OF COMPLEX ORGANIC CONTAMINANTS IN WATER WITH RAMAN SPECTROSCOPY

    EPA Science Inventory

    Pesticides and industrial chemicals are typically complex organic molecules with multiple heteroatoms that can ionize, tautomerize, and form various types of hydrates in water. However, conceptual models for predicting the fate of these chemicals in the environment ignore these ...

  18. CHEMICAL DYNAMICS OF HYDROPHOBIC ORGANIC CONTAMINANTS DURING RESUSPENSION

    EPA Science Inventory

    Laboratory experiments were designed to study the chemical-particle dynamics of toxic hydrophobic organics during resuspension episodes using a particle entrainment simulator (PES). The purpose was to obtain insight into chemical transport mechanisms during resuspension. Informat...

  19. Removal of organic contaminants by RO and NF membranes

    NASA Technical Reports Server (NTRS)

    Yoon, Yeomin; Lueptow, Richard M.

    2005-01-01

    Rejection characteristics of organic and inorganic compounds were examined for six reverse osmosis (RO) membranes and two nanofiltration (NF) membranes that are commercially available. A batch stirred-cell was employed to determine the membrane flux and the solute rejection for solutions at various concentrations and different pH conditions. The results show that for ionic solutes the degree of separation is influenced mainly by electrostatic exclusion, while for organic solutes the removal depends mainly upon the solute radius and molecular structure. In order to provide a better understanding of rejection mechanisms for the RO and NF membranes, the ratio of solute radius (r(i,s)) to effective membrane pore radius (r(p)) was employed to compare rejections. An empirical relation for the dependence of the rejection of organic compounds on the ratio r(i,s)/r(p) is presented. The rejection for organic compounds is over 75% when r(i,s)/r(p) is greater than 0.8. In addition, the rejection of organic compounds is examined using the extended Nernst-Planck equation coupled with a steric hindrance model. The transport of organic solutes is controlled mainly by diffusion for the compounds that have a high r(i,s)/r(p) ratio, while convection is dominant for compounds that have a small r(i,s)/r(p) ratio. c2005 Elsevier B.V. All rights reserved.

  20. Influence of organic contamination on laser induced damage of multilayer dielectric mirrors by subpicosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Favrat, O.; Sozet, M.; Tovena-Pécault, I.; Lamaignère, L.; Néauport, J.

    2014-10-01

    Laser induced damage of optical components is often a limiting factor for the development of high power lasers. Indeed, for many years, organic contamination is identified as a factor decreasing the laser induced damage threshold of optical surfaces, limiting the use of high fluencies. Also, for the development of its laser facilities, Laser MégaJoule and PETawatt Aquitaine Laser, the Commissariat à l'Energie Atomique et aux Energies Alternatives investigates the influence of organic contamination on the performances of the optical components. Actually, although great care is provided on the cleanliness of the optics, organic volatile compounds outgassed from surrounding materials can be adsorbed by the sensitive surfaces during its timelife. Thus, for this study, performances of clean and contaminated multilayer dielectric mirrors are compared. Contamination is intentionally realized either by controlled protocols or by exposing optics inside the laser facilities. Qualification and quantification of the organic contamination is realized by automated thermal desorption and gas chromatography coupled with mass spectrometry. Laser induced damage threshold of clean and contaminated mirrors are then investigated by 1053 nm laser at 670 fs.

  1. Organic adlayer on inorganic materials: XPS analysis selectivity to cope with adventitious contamination

    NASA Astrophysics Data System (ADS)

    Landoulsi, Jessem; Genet, Michel J.; Fleith, Sandrine; Touré, Yetioman; Liascukiene, Irma; Méthivier, Christophe; Rouxhet, Paul G.

    2016-10-01

    This work addresses the ubiquitous presence of organic contaminants at inorganic solid surfaces and the improvement of XPS analysis selectivity to cope with it. Water contact angle measurements showed that the adsorption of organic contaminants occurs readily in ambient air, and faster and more extensively under high vacuum. It is stronger on stainless steel (SS) compared to silica and is significantly reduced when SS is sterilized by autoclaving. The reliability of XPS data was evaluated (selectivity, precision, accuracy) by correlations between spectral data incorporating a large amount of results obtained with different XPS spectrometers on SS and glass samples cleaned in different ways and conditioned with several biomacromolecules. The methodology used allows a discrimination to be made between contaminants and deliberately adsorbed biomacromolecules, and offers perspectives for tracking the source of contamination. Furthermore, a discrimination can be made between oxygen from the organic adlayer and oxygen from the substrate, and the O 1s component above 532.0 eV observed for SS is shown to be due to organic contaminants rather than adsorbed water. This approach offers new perspectives to examine the interactions (displacement or not) between contaminants and compounds of interest, e.g. proteins, at the stage of the adsorption process.

  2. Molecular Scale Determinants of Organic Contaminant and Pesticide Sorption by Clays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Clay minerals and soil organic matter (SOM) are generally considered to be the most important soil components in the sorption of aqueous phase organic contaminants. During the past 25 years, much emphasis has been placed on the dominant role of SOM in sorption. However, there is increasing evidence...

  3. Leaching of chloride, sulphate, heavy metals, dissolved organic carbon and phenolic organic pesticides from contaminated concrete.

    PubMed

    Van Praagh, M; Modin, H

    2016-10-01

    Concrete samples from demolition waste of a former pesticide plant in Sweden were analysed for total contents and leachate concentrations of potentially hazardous inorganic substances, TOC, phenols, as well as for pesticide compounds such as phenoxy acids, chlorophenols and chlorocresols. Leachates were produced by means of modified standard column leaching tests and pH-stat batch tests. Due to elevated contents of chromium and lead, as well as due to high chloride concentrations in the first leachate from column tests at L/S 0.1, recycling of the concrete as a construction material in groundworks is likely to be restricted according to Swedish guidelines. The studied pesticide compounds appear to be relatively mobile at the materials own pH>12, 12, 9 and 7. Potential leaching of pesticide residues from recycled concrete to ground water and surface water might exceed water quality guidelines for the remediation site and the EU Water Framework Directive. Results of this study stress the necessity to systematically study the mechanism behind mobility of organic contaminants from alkaline construction and demolition wastes rather than rely on total content limit values.

  4. Leaching of chloride, sulphate, heavy metals, dissolved organic carbon and phenolic organic pesticides from contaminated concrete.

    PubMed

    Van Praagh, M; Modin, H

    2016-10-01

    Concrete samples from demolition waste of a former pesticide plant in Sweden were analysed for total contents and leachate concentrations of potentially hazardous inorganic substances, TOC, phenols, as well as for pesticide compounds such as phenoxy acids, chlorophenols and chlorocresols. Leachates were produced by means of modified standard column leaching tests and pH-stat batch tests. Due to elevated contents of chromium and lead, as well as due to high chloride concentrations in the first leachate from column tests at L/S 0.1, recycling of the concrete as a construction material in groundworks is likely to be restricted according to Swedish guidelines. The studied pesticide compounds appear to be relatively mobile at the materials own pH>12, 12, 9 and 7. Potential leaching of pesticide residues from recycled concrete to ground water and surface water might exceed water quality guidelines for the remediation site and the EU Water Framework Directive. Results of this study stress the necessity to systematically study the mechanism behind mobility of organic contaminants from alkaline construction and demolition wastes rather than rely on total content limit values. PMID:27449537

  5. Removal of Biologically Active Organic Contaminants using Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor); Banks, Michael A. (Inventor); Banks, Eric B. (Inventor)

    2003-01-01

    Biomedical devices that are to come into contact with living tissue, such as prosthetic and other implants for the human body and the containers used to store and transport them, are together cleaned of non-living, but biologically active organic materials, including endotoxins such as lipopolysaccharides, and assembled into a hermetically sealed package without recontamination. This is achieved by cleaning both the device and package components together in an apparatus, which includes a hermetically sealed chamber, in which they are contacted with atomic oxygen which biocleans them, by oxidizing the biologically active organic materials. The apparatus also includes means for manipulating the device and container and hermetically sealing the cleaned device into the cleaned container to form the package. A calibrated witness coupon visually indicates whether or not the device and container have received enough exposure to the atomic oxygen to have removed the organic materials from their surfaces. Gamma radiation is then used to sterilize the device in the sealed container.

  6. Predictive relationships for uptake of organic contaminants by hybrid poplar trees

    SciTech Connect

    Burken, J.G.; Schnoor, J.L.

    1998-11-01

    Twelve organic compounds commonly found at hazardous waste sites were studied for uptake by hybrid poplar trees. The vegetative uptake of many of these compounds has not previously been demonstrated for plant species being utilized for phytoremediation, such as hybrid poplar trees. Experiments were conducted hydroponically utilizing {sup 14}C-labeled compounds to ascertain translocation and fate. Predictive relationships for the translocation and partitioning to plant tissues were developed from the experimental data. Translocation and partitioning relationships based on compounds` octanol-water partitioning coefficients produced the best results, but the relationships did not allow for fully accurate prediction of each contaminant`s fate. Translocation and subsequent transpiration of volatile organic compounds (VOCs) from the leaves to the atmosphere was shown to be a significant pathway. As full-scale phytoremediation systems are deliberated, the pathways investigated here should be considered in terms of a contaminant removal mechanism and potential contamination of the vegetation.

  7. Temporal and Spatial Variation of Atmospherically Deposited Organic Contaminants at High Elevation in Yosemite National Park, California, USA

    EPA Science Inventory

    Atmospherically deposited organic contaminants in the Sierra Nevada mountains of California, USA, have exceeded some thresholds of concern, but the spatial and temporal distributions of contaminants in the mountains are not well known. The present study evaluated (1) whether the...

  8. BIOGEOCHEMISTRY OF CHLORINATED ORGANIC CONTAMINANTS IN AQUATIC ECOSYSTEMS

    EPA Science Inventory

    Over the last several years we have conducted both laboratory and field studies to develop a better understanding of the movement of chlorinated organic compounds through aquatic ecosystems, with special emphasis on the differential movement of these compounds due to physical/che...

  9. Green Photocatalysis for Degradation of Organic Contaminants: A Review

    EPA Science Inventory

    Many organic pesticides that were banned a few decades ago, as well as those that are currently in use in many parts of the world, pose some serious threat to human life and the ecosystem because of their persistent and bioaccumulative nature. In the recent years advanced oxidati...

  10. The interplay between habitat structure and chemical contaminants on biotic responses of benthic organisms.

    PubMed

    Mayer-Pinto, Mariana; Matias, Miguel G; Coleman, Ross A

    2016-01-01

    Habitat structure influences the diversity and distribution of organisms, potentially affecting their response to disturbances by either affecting their 'susceptibility' or through the provision of resources that can mitigate impacts of disturbances. Chemical disturbances due to contamination are associated with decreases in diversity and functioning of systems and are also likely to increase due to coastal urbanisation. Understanding how habitat structure interacts with contaminants is essential to predict and therefore manage such effects, minimising their consequences to marine systems. Here, we manipulated two structurally different habitats and exposed them to different types of contaminants. The effects of contamination and habitat structure interacted, affecting species richness. More complex experimental habitats were colonized by a greater diversity of organisms than the less complex habitats. These differences disappeared, however, when habitats were exposed to contaminants, suggesting that contaminants can override effects of habitats structure at small spatial scales. These results provide insight into the complex ways that habitat structure and contamination interact and the need to incorporate evidence of biotic responses from individual disturbances to multiple stressors. Such effects need to be taken into account when designing and planning management and conservation strategies to natural systems. PMID:27168991

  11. The interplay between habitat structure and chemical contaminants on biotic responses of benthic organisms

    PubMed Central

    Matias, Miguel G.; Coleman, Ross A.

    2016-01-01

    Habitat structure influences the diversity and distribution of organisms, potentially affecting their response to disturbances by either affecting their ‘susceptibility’ or through the provision of resources that can mitigate impacts of disturbances. Chemical disturbances due to contamination are associated with decreases in diversity and functioning of systems and are also likely to increase due to coastal urbanisation. Understanding how habitat structure interacts with contaminants is essential to predict and therefore manage such effects, minimising their consequences to marine systems. Here, we manipulated two structurally different habitats and exposed them to different types of contaminants. The effects of contamination and habitat structure interacted, affecting species richness. More complex experimental habitats were colonized by a greater diversity of organisms than the less complex habitats. These differences disappeared, however, when habitats were exposed to contaminants, suggesting that contaminants can override effects of habitats structure at small spatial scales. These results provide insight into the complex ways that habitat structure and contamination interact and the need to incorporate evidence of biotic responses from individual disturbances to multiple stressors. Such effects need to be taken into account when designing and planning management and conservation strategies to natural systems. PMID:27168991

  12. Associations of free-living bacteria and dissolved organic compounds in a plume of contaminated groundwater

    USGS Publications Warehouse

    Harvey, R.W.; Barber, L.B.; ,

    1992-01-01

    Associations of free-living bacteria (FLB) and dissolved organic contaminants in a 4-km-long plume of sewage-contaminated groundwater were investigated. Abundance of FLB in the core of the plume (as delineated by maximum specific conductance) steadily decreased in the direction of flow from a point 0.25 km downgradient from the source to the toe of the plume. At 0.25 km downgradient, FLB comprised up to 31% of the total bacterial population, but constituted < 7% of the population at 2 km downgradient. Abundance of FLB correlated strongly (r = 0.80 n = 23) with total dissolved organic carbon (DOC) in contaminated groundwater between 0.64 and 2.1 km downgradient, although distributions of individual contaminants such as di-, tri- and tetrachloroethene were highly variable, and their association with FLB less clear. Numbers of FLB in the downgradient portion of the plume which is contaminated with branched-chain alkylbenzenesulfonate (ABS) surfactants were low (< 5??108/L) in spite of relatively high levels of DOC (up to 4 mg/L). However, abundance of FLB correlated strongly with non-surfactant DOC along vertical transects through the plume. The ratio of FLB to DOC and the ratio of FLB to attached bacteria generally decreased in the direction of flow and, consequently, with the age of the organic contaminants.

  13. Removal of volatile and semivolatile organic contamination from soil by air and steam flushing.

    PubMed

    Sleep, B E; McClure, P D

    2001-07-01

    A soil core, obtained from a contaminated field site, contaminated with a mixture of volatile and semivolatile organic compounds (VOC and SVOC) was subjected to air and steam flushing. Removal rates of volatile and semivolatile organic compounds were monitored during flushing. Air flushing removed a significant portion of the VOC present in the soil, but a significant decline in removal rate occurred due to decreasing VOC concentrations in the soil gas phase. Application of steam flushing after air flushing produced a significant increase in contaminant removal rate for the first 4 to 5 pore volumes of steam condensate. Subsequently, contaminant concentrations decreased slowly with additional pore volumes of steam flushing. The passage of a steam volume corresponding to 11 pore volumes of steam condensate reduced the total VOC concentration in the soil gas (at 20 degrees C) by a factor of 20 to 0.07 mg/l. The corresponding total SVOC concentration in the condensate declined from 11 to 3 mg/l. Declines in contaminant removal rates during both air and steam flushing indicated rate-limited removal consistent with the persistence of a residual organic phase, rate-limited desorption, or channeling. Pressure gradients were much higher for steam flushing than for air flushing. The magnitude of the pressure gradients encountered during steam flushing for this soil indicates that, in addition to rate-limited contaminant removal, the soil permeability (2.1 x 10(-9) cm2) would be a limiting factor in the effectiveness of steam flushing. PMID:11475159

  14. Transport behaviour and natural attenuation of organic contaminants at spill sites.

    PubMed

    Schirmer, Mario; Butler, Barbara J

    2004-12-15

    Organic contaminants pose a significant threat to groundwater resources. These contaminants are often released as non-aqueous phase liquids (NAPLs) during spills of, for example, gasoline, crude oil, creosote, coal tar or chlorinated solvents. Once released, the liquids seep downward and dissolve into the groundwater. In many cases, the impacted groundwater contains a mixture of contaminants, either due to the complexity of the NAPL (e.g., gasoline) or due to co-disposal/co-spillage (e.g., landfill leachates). Many organic contaminants are hazardous to human health and the environment and therefore threaten our potable water resources and natural ecosystems. Active remediation of contaminated groundwater is often very expensive so that cost-effective alternatives have to be found. If natural attenuation is intended to be used as a means of achieving specific remedial objectives at a contaminated site, it will require a sound understanding of the ongoing processes as well as careful control and monitoring ("monitored natural attenuation" (MNA)). Therefore, a major goal of remediation research today is to develop methods to predict the mass fate of multiple organic compounds in heterogeneous aquifers under natural conditions.

  15. Exploring the role of shelf sediments in the Arctic Ocean in determining the Arctic contamination potential of neutral organic contaminants.

    PubMed

    Armitage, James M; Choi, Sung-Deuk; Meyer, Torsten; Brown, Trevor N; Wania, Frank

    2013-01-15

    The main objective of this study was to model the contribution of shelf sediments in the Arctic Ocean to the total mass of neutral organic contaminants accumulated in the Arctic environment using a standardized emission scenario for sets of hypothetical chemicals and realistic emission estimates (1930-2100) for polychlorinated biphenyl congener 153 (PCB-153). Shelf sediments in the Arctic Ocean are shown to be important reservoirs for neutral organic chemicals across a wide range of partitioning properties, increasing the total mass in the surface compartments of the Arctic environment by up to 3.5-fold compared to simulations excluding this compartment. The relative change in total mass for hydrophobic organic chemicals with log air-water partition coefficients ≥0 was greater than for chemicals with properties similar to typical POPs. The long-term simulation of PCB-153 generated modeled concentrations in shelf sediments in reasonable agreement with available monitoring data and illustrate that the relative importance of shelf sediments in the Arctic Ocean for influencing surface ocean concentrations (and therefore exposure via the pelagic food web) is most pronounced once primary emissions are exhausted and secondary sources dominate. Additional monitoring and modeling work to better characterize the role of shelf sediments for contaminant fate is recommended.

  16. Measurement of Psychiatric Treatment Adherence

    PubMed Central

    Sajatovic, Martha; Velligan, Dawn; Weiden, Peter J.; Valenstein, Marcia; Ogedegbe, Gbenga

    2014-01-01

    Objective Nonadherence to medications for mental disorders substantially limits treatment effectiveness and results in higher rates of relapse, hospitalization, and disability. Accurate measurement of medication adherence is important not only in adherence research, but also in clinical trials in which medications are being evaluated, and in clinical practice where failure to detect nonadherence results in premature medication changes, unnecessary polypharmacy, and greater likelihoods of functional deteriorations and hospitalizations. This is a review of psychiatric treatment adherence methods and measures arising from a meeting on “Methodological Challenges in Psychiatric Treatment Adherence Research” held on September 27-28, 2007 in Bethesda, MD and organized by the National Institute of Mental Health (NIMH). Methods This paper reviews the range of modalities currently available for assessing adherence behavior including pill counts, pharmacy records, technology-assisted monitoring, biological assays, and a range of self-report and interviewer-rated scales. Measures of adherence attitudes are also reviewed. Results Each of the adherence measures described are imperfect estimates of actual medication ingestion but each provides informative estimates of adherence or the attitudinal factors associated with adherence. Measure selection depends on a range of factors including the patient sample, the context in which the measure is being used, and the clinical outcomes expected from various levels of nonadherence. The use of multiple measures of adherence is encouraged to balance the limitations of individual measures. Conclusion While adherence assessment has become increasingly sophisticated in recent years there remains a need for refinement and expansion on currently available methods and measures. PMID:21109048

  17. Assessing Changes to Organic Contaminant Fluxes from Contaminated Sediments Following Dam Removal in an Urbanized River

    EPA Science Inventory

    Restoration of rivers and their associated ecosystems is a growing priority for government agencies (e.g., NOAA, USDA), as well as conservation organizations. Dam removal is a major component of many restoration projects credited with reintroducing fish species, improving water ...

  18. Application of Passive Sampling for Measuring Dissolved Concentrations of Organic Contaminants in the Water Column at Three U.S. EPA Marine Superfund Sites

    EPA Science Inventory

    At contaminated sediment sites, including U.S. EPA Superfund sites, it is critical to measure water column concentrations of freely dissolved contaminants to understand the complete exposure of aquatic organisms to hydrophobic organic contaminants (HOCs). Historically acquiring ...

  19. Application of Passive Sampling for Measuring Dissolved Concentrations of Organic Contaminants in the Water Column at Three U.S. EPA Marine Superfund Sites.

    EPA Science Inventory

    At contaminated sediment sites, including U.S. EPA Superfund sites, it is critical to measure water column concentrations of freely dissolved contaminants to understand the complete exposure of aquatic organisms to hydrophobic organic contaminants (HOCs). Historically, acquiring...

  20. Importance of structural makeup of biopolymers for organic contaminant sorption.

    PubMed

    Wang, Xilong; Xing, Baoshan

    2007-05-15

    Sorption of pyrene, phenanthrene, naphthalene, and 1-naphthol by original (lignin, chitin, and cellulose) and coated biopolymers was examined. Organic carbon normalized distribution coefficients (Koc) of all compounds by the original biopolymers followed the order lignin > chitin > cellulose, in line with the order of their hydrophobicity. Hydrophobicity of structurally similar organic compounds is the main factor determining their ability to occupy sorption sites in biopolymers. Specific interactions (e.g., H-bonding) between 1-naphthol and chitin or cellulose increased its ability to occupy sorption sites. Lignin coating resulted in an increased Koc for phenanthrene (13.6 times for chitin and 6.9 times for cellulose) and 1-naphthol (6.0 times for chitin and 3.7 times for cellulose) relative to the acetone-treated chitin and cellulose. Also, these coated biopolymers had increased isotherm nonlinearity, due to the newly formed condensed domains. An increase in phenanthrene and 1-naphthol sorption by lignin-coated biopolymers as compared to chitin and cellulose was contributed by the newly created high-energy sites in condensed domains and coated lignin. Results of this study highlight the importance of the structural makeup of biopolymers in controlling the sorption of hydrophobic organic compounds.

  1. Effects of dissolved organic matter from a eutrophic lake on the freely dissolved concentrations of emerging organic contaminants.

    PubMed

    Xiao, Yi-Hua; Huang, Qing-Hui; Vähätalo, Anssi V; Li, Fei-Peng; Chen, Ling

    2014-08-01

    The authors studied the effects of dissolved organic matter (DOM) on the bioavailability of bisphenol A (BPA) and chloramphenicol by measuring the freely dissolved concentrations of the contaminants in solutions containing DOM that had been isolated from a mesocosm in a eutrophic lake. The abundance and aromaticity of the chromophoric DOM increased over the 25-d mesocosm experiment. The BPA freely dissolved concentration was 72.3% lower and the chloramphenicol freely dissolved concentration was 56.2% lower using DOM collected on day 25 than using DOM collected on day 1 of the mesocosm experiment. The freely dissolved concentrations negatively correlated with the ultraviolent absorption coefficient at 254 nm and positively correlated with the spectral slope of chromophoric DOM, suggesting that the bioavailability of these emerging organic contaminants depends on the characteristics of the DOM present. The DOM-water partition coefficients (log KOC ) for the emerging organic contaminants positively correlated with the aromaticity of the DOM, measured as humic acid-like fluorescent components C1 (excitation/emission=250[313]/412 nm) and C2 (excitation/emission=268[379]/456 nm). The authors conclude that the bioavailability of emerging organic contaminants in eutrophic lakes can be affected by changes in the DOM.

  2. Oxidation of organic contaminants by manganese oxide geomedia for passive urban stormwater treatment systems.

    PubMed

    Grebel, Janel E; Charbonnet, Joseph A; Sedlak, David L

    2016-01-01

    To advance cost-effective strategies for removing trace organic contaminants from urban runoff, the feasibility of using manganese oxides as a geomedia amendment in engineered stormwater infiltration systems to oxidize organic contaminants was evaluated. Ten representative organic chemicals that have previously been detected in urban stormwater were evaluated for reactivity in batch experiments with birnessite. With respect to reactivity, contaminants could be classified as: highly reactive (e.g., bisphenol A), moderately reactive (e.g., diuron) and unreactive (e.g., tris(2-chloro-1-propyl)phosphate). Bisphenol A and diuron reacted with birnessite to produce a suite of products, including ring-cleavage products for bisphenol A and partially dechlorinated products for diuron. Columns packed with manganese oxide-coated sand were used evaluate design parameters for an engineered infiltration system, including necessary contact times for effective treatment, as well as the impacts of stormwater matrix variables, such as solution pH, concentration of natural organic matter and major anions and cations. The manganese oxide geomedia exhibited decreased reactivity when organic contaminants were oxidized, especially in the presence of divalent cations, bicarbonate, and natural organic matter. Under typical conditions, the manganese oxides are expected to retain their reactivity for 25 years.

  3. Role of benthic communities in organic contaminant transport and fate. 2: Bioaccumulation and biotransformation

    SciTech Connect

    Dickhut, R.M.; Schaffner, L.C.; Lay, P.W.; Mitra, S. |

    1994-12-31

    Numerous macrobenthic organisms from lower Chesapeake Bay have been observed to rapidly accumulate and transform a series of organic contaminants (OCs). Bioaccumulation and biotransformation vary both within and among major taxa, and with the OC physical-chemical properties. Bioaccumulation of OCs is rapid for various organisms regardless of feeding behavior indicating that uptake of contaminants from the dissolved phase may be important. Comparison of OC and metabolite body burdens to those in the corresponding sediment indicate three types of behavior for OC fluxes through the organisms over 56 days of exposure to contaminated sediments: steady state between contaminant uptake and elimination, faster uptake than elimination corresponding to bioaccumulation, and rapid loss relative to uptake, with decreasing bioaccumulation factors with time. OC loss mechanisms from operationally defined detectable pools in benthic biota may include: elimination of parent compound or metabolites, and binding of reactive metabolites to cellular structures. OC metabolite production and loss rates in benthic macrofauna from Chesapeake Bay are currently under investigation. Bioaccumulation and transformation of OCs by benthic organisms are of importance in determining their effects, including trophic transfer of organic pollutants, on aquatic ecosystems.

  4. Determination of biological removal of recalcitrant organic contaminants in coal gasification waste water.

    PubMed

    Ji, Qinhong; Tabassum, Salma; Yu, Guangxin; Chu, Chunfeng; Zhang, Zhenjia

    2015-01-01

    Coal gasification waste water treatment needed a sustainable and affordable plan to eliminate the organic contaminants in order to lower the potential environmental and human health risk. In this paper, a laboratory-scale anaerobic-aerobic intermittent system carried out 66 operational cycles together for the treatment of coal gasification waste water and the removal capacity of each organic pollutant. Contaminants included phenols, carboxylic acids, long-chain hydrocarbons, and heterocyclic compounds, wherein the relative content of phenol is up to 57.86%. The long-term removal of 77 organic contaminants was evaluated at different hydraulic retention time (anaerobic24 h + aerobic48 h and anaerobic48 h +aerobic48 h). Contaminant removal ranged from no measurable removal to near-complete removal with effluent concentrations below the detection limit. Contaminant removals followed one of four trends: steady-state removal throughout, increasing removal to steady state (acclimation), decreasing removal, and no removal. Organic degradation and transformation in the reaction were analysed by gas chromatography/mass spectrometry technology.

  5. Contamination of vegetables, fruits and soil with geohelmints eggs on organic farms in Poland.

    PubMed

    Kłapeć, Teresa; Borecka, Anna

    2012-01-01

    The objective of this study was to evaluate the contamination of vegetables, fruits and soil with zoonotic parasite eggs on organic and conventional farms in south-eastern Poland. To evaluate the contamination with eggs of zoonotic parasites, examinations were conducted on 8 conventional and 11 organic farms in south-eastern Poland from May-October in 2008 and 2009. The following fruit and vegetables were selected for the experiment: strawberry, leek, onion, carrot, zucchini, beetroot, parsley, potatoes, celery, rhubarb, lettuce, cabbage, broccoli, pumpkin, young beetroot leaves, cauliflower, French beans, turnip, fennel and sorrel. A total of 187 samples of vegetables, fruits and soil were examined by means of a modified flotation method according to Quinn et al. (1980). Contamination with Ascaris, Trichuris and Toxocara eggs was found, with a higher number of positive samples revealed on conventional (34.7%), compared to organic farms (18.9%). The level of contamination in soil samples from conventional farms was higher (88.5% positive samples), than of those from organic farms (32.8%). Of the 15 geohelmints eggs, positive samples were found in vegetables: 9 Toxocara eggs, 4 Ascaris eggs and 2 Trichuris eggs. No geohelmints eggs were observed in the strawberry samples. The consumption of vegetables and fruits contaminated with the eggs of parasites may be the cause of parasitoses in humans. Stricter sanitary standards on farms of all types may limit the incidence of parasitic zoonoses.

  6. A mixture of environmental organic contaminants in lake sediments affects hatching from Daphnia resting eggs.

    PubMed

    Möst, Markus; Chiaia-Hernandez, Aurea C; Frey, Martin P; Hollender, Juliane; Spaak, Piet

    2015-02-01

    Despite the relevance of resting eggs for ecology and evolution of many aquatic organisms and their exposure to contaminants accumulating in sediments, ecotoxicological studies using resting eggs are vastly underrepresented. The authors established a method to perform exposure assays with resting eggs produced by the Daphnia longispina species complex, key species in large lake ecosystems. A mixture of organic contaminants previously detected in sediments of Lake Greifensee was selected to test the potential effect of organic contaminants present in sediments on the hatching process. Resting eggs were exposed to a mix of 10 chemicals, which included corrosion inhibitors, biocides, pesticides, and personal care products, for a period of 15 d. Using an automated counting software, the authors found a significant increase in hatching success in the exposed resting eggs compared with controls. Such an effect has not yet been reported from ecotoxicological assays with resting eggs. Possible mechanistic explanations as well as the potential implications on the ecology and evolution of aquatic species that rely on a resting egg banks are discussed. Observed increased mortality and developmental abnormalities for hatchlings in the exposure treatments can be explained by toxic contaminant concentrations. The results of the present study highlight the need for additional studies assessing the effects of organic contaminants on resting egg banks and aquatic ecosystems.

  7. Contamination of vegetables, fruits and soil with geohelmints eggs on organic farms in Poland.

    PubMed

    Kłapeć, Teresa; Borecka, Anna

    2012-01-01

    The objective of this study was to evaluate the contamination of vegetables, fruits and soil with zoonotic parasite eggs on organic and conventional farms in south-eastern Poland. To evaluate the contamination with eggs of zoonotic parasites, examinations were conducted on 8 conventional and 11 organic farms in south-eastern Poland from May-October in 2008 and 2009. The following fruit and vegetables were selected for the experiment: strawberry, leek, onion, carrot, zucchini, beetroot, parsley, potatoes, celery, rhubarb, lettuce, cabbage, broccoli, pumpkin, young beetroot leaves, cauliflower, French beans, turnip, fennel and sorrel. A total of 187 samples of vegetables, fruits and soil were examined by means of a modified flotation method according to Quinn et al. (1980). Contamination with Ascaris, Trichuris and Toxocara eggs was found, with a higher number of positive samples revealed on conventional (34.7%), compared to organic farms (18.9%). The level of contamination in soil samples from conventional farms was higher (88.5% positive samples), than of those from organic farms (32.8%). Of the 15 geohelmints eggs, positive samples were found in vegetables: 9 Toxocara eggs, 4 Ascaris eggs and 2 Trichuris eggs. No geohelmints eggs were observed in the strawberry samples. The consumption of vegetables and fruits contaminated with the eggs of parasites may be the cause of parasitoses in humans. Stricter sanitary standards on farms of all types may limit the incidence of parasitic zoonoses. PMID:23020033

  8. Biomagnification of persistent organic contaminants in Great Slave Lake food webs

    SciTech Connect

    Evans, M.S.; Muir, D.; Lockhart, L.

    1994-12-31

    Great Slave Lake is a large, subarctic lake which receives the majority of its water from the Slave, Peace, and Athabasca Rivers watershed. Increased development in the southern region of the watershed may provide a significant source of organic contaminants to the lake in addition to contaminants entering the lake via direct atmospheric deposition. Here the authors report the results of a study comparing organic contaminant concentrations in lake trout, burbot, and whitefish collected near the Slave River outflow and in a region of Great Slave Lake which is believed to be minimally affected by the Slave River. They also use stable isotope analyses to infer spatial differences in fish feeding habits between the two regions of the lake and to investigate how food habits may affect organic contaminant biomagnification. Finally, the authors compare their Great Slave Lake data with studies conducted from other regions of the Arctic and subarctic. This allows them to infer how the Slave River inflow may affect organic contaminant concentrations and biomagnification in the Great Slave Lake ecosystem.

  9. Studies on organic and in-organic biostimulants in bioremediation of diesel-contaminated arable soil.

    PubMed

    Nwankwegu, Amechi S; Orji, Michael U; Onwosi, Chukwudi O

    2016-11-01

    In this study, use of inorganic fertilizer (N.P.K) was compared with organic manure (compost) in the bioremediation of diesel-polluted agricultural soil over a two-month period. Renewal by enhanced natural attenuation was used as control. The results revealed that total petroleum hydrocarbon removal from polluted soil was 71.40 ± 5.60% and 93.31 ± 3.60% for N.P.K and compost amended options, respectively. The control (natural attenuation) had 57.90 ± 3.98% of total petroleum hydrocarbon removed. Experimental data fitted second order kinetic model adequately for compost amended option. The fertilizer amended option was found to be 1.04 times slower (k2 = 4.00 ± 1.40 × 10(-7)gmg(-1)d(-1), half-life = 28.15 d) than compost amended option (k2 = 1.39 ± 0.54 × 10(-5) gmg(-1)d(-1), half-life = 8.10 d) but 1.21 times (20.6%) faster than the control (k2 = 2.57 ± 0.16 × 10(-7) gmg(-1)d(-1), half-life = 43.81 d). The hydrocarbon utilizers isolated from the diesel contaminated soil were: Bacillus nealsoni, Micrococcus luteus, Aspergillus awamori, and Fusarium proliferatum. The phytotoxicity test showed that germination indices for natural attenuation (control), fertilizer (NPK) and compost amended options were 34%, 56%, and 89%, respectively. PMID:27494315

  10. Studies on organic and in-organic biostimulants in bioremediation of diesel-contaminated arable soil.

    PubMed

    Nwankwegu, Amechi S; Orji, Michael U; Onwosi, Chukwudi O

    2016-11-01

    In this study, use of inorganic fertilizer (N.P.K) was compared with organic manure (compost) in the bioremediation of diesel-polluted agricultural soil over a two-month period. Renewal by enhanced natural attenuation was used as control. The results revealed that total petroleum hydrocarbon removal from polluted soil was 71.40 ± 5.60% and 93.31 ± 3.60% for N.P.K and compost amended options, respectively. The control (natural attenuation) had 57.90 ± 3.98% of total petroleum hydrocarbon removed. Experimental data fitted second order kinetic model adequately for compost amended option. The fertilizer amended option was found to be 1.04 times slower (k2 = 4.00 ± 1.40 × 10(-7)gmg(-1)d(-1), half-life = 28.15 d) than compost amended option (k2 = 1.39 ± 0.54 × 10(-5) gmg(-1)d(-1), half-life = 8.10 d) but 1.21 times (20.6%) faster than the control (k2 = 2.57 ± 0.16 × 10(-7) gmg(-1)d(-1), half-life = 43.81 d). The hydrocarbon utilizers isolated from the diesel contaminated soil were: Bacillus nealsoni, Micrococcus luteus, Aspergillus awamori, and Fusarium proliferatum. The phytotoxicity test showed that germination indices for natural attenuation (control), fertilizer (NPK) and compost amended options were 34%, 56%, and 89%, respectively.

  11. Vitrification of cesium-contaminated organic ion exchange resin

    SciTech Connect

    Sargent, T.N. Jr.

    1994-08-01

    Vitrification has been declared by the Environmental Protection Agency (USEPA) as the Best Demonstrated Available Technology (BDAT) for the permanent disposal of high-level radioactive waste. Savannah River Site currently uses a sodium tetraphenylborate (NaTPB) precipitation process to remove Cs-137 from a wastewater solution created from the processing of nuclear fuel. This process has several disadvantages such as the formation of a benzene waste stream. It has been proposed to replace the precipitation process with an ion exchange process using a new resorcinol-formaldehyde resin developed by Savannah River Technical Center (SRTC). Preliminary tests, however, showed that problems such as crust formation and a reduced final glass wasteform exist when the resin is placed in the melter environment. The newly developed stirred melter could be capable of overcoming these problems. This research explored the operational feasibility of using the stirred tank melter to vitrify an organic ion exchange resin. Preliminary tests included crucible studies to determine the reducing potential of the resin and the extent of oxygen consuming reactions and oxygen transfer tests to approximate the extent of oxygen transfer into the molten glass using an impeller and a combination of the impeller and an external oxygen transfer system. These preliminary studies were used as a basis for the final test which was using the stirred tank melter to vitrify nonradioactive cesium loaded organic ion exchange resin. Results from this test included a cesium mass balance, a characterization of the semi-volatile organic compounds present in the off gas as products of incomplete combustion (PIC), a qualitative analysis of other volatile metals, and observations relating to the effect the resin had on the final redox state of the glass.

  12. Transport of organic contaminants in geomembranes under stress

    SciTech Connect

    Xiao, S. ); Moresoli, C. . Dept. of Chemical Engineering); Burczyk, A. ); Pintauro, P.; De Kee, D. . Dept. of Chemical Engineering)

    1999-07-01

    The transport properties of aqueous solutions of benzene, dichloromethane, and trichloroethylene through extended polyvinyl chloride and high-density polyethylene geomembranes are investigated. It is found that extension enhances the permeation rates of the penetrants through polyvinyl chloride geomembranes, and the opposite effect is found in the case of high-density polyethylene. This difference in response is attributed to the type of structural change, which occurred as a result of the extension. The diffusivities of a mixture of the three organic solvents through the geomembranes are also determined.

  13. Remediation of Groundwater Contaminated with Organics and Radionuclides - An Innovative Approach Eases Traditional Hurdles

    SciTech Connect

    Scott, J.; Case, N.; Coltman, K.

    2003-02-25

    Traditional approaches to the remediation of contaminated groundwater, such as pump-and-treat, have been used for many years for the treatment of groundwater contaminated with various organics. However the treatment of groundwater contaminated with organics and radionuclides has been considerably more challenging. Safety and Ecology Corporation (SEC) was recently faced with these challenges while designing a remediation system for the remediation of TCE-contaminated groundwater and soil at the RMI Extrusion Plant in Ashtabula, OH. Under contract with RMI Environmental Services (RMIES), SEC teamed with Regenesis, Inc. to design, implement, and execute a bioremediation system to remove TCE and associated organics from groundwater and soil that was also contaminated with uranium and technetium. The SEC-Regenesis system involved the injection of Hydrogen Release Compound (HRC), a natural attenuation accelerant that has been patented, designed, and produced by Regenesis, to stimulate the reductive dechlorination and remediation of chlorinated organics in subsurface environments. The compound was injected using direct-push Geoprobe rods over a specially designed grid system through the zone of contaminated groundwater. The innovative approach eliminated the need to extract contaminated groundwater and bypassed the restrictive limitations listed above. The system has been in operation for roughly six months and has begun to show considerable success at dechlorinating and remediating the TCE plume and in reducing the radionuclides into insoluble precipitants. The paper will provide an overview of the design, installation, and initial operation phase of the project, focusing on how traditional design challenges of remediating radiologically contaminated groundwater were overcome. The following topics will be specifically covered: a description of the mechanics of the HRC technology; an assessment of the applicability of the HRC technology to contaminated groundwater plumes

  14. A non-equilibrium model for predicting bioaccumulation of organic contaminants in aquatic food-webs

    SciTech Connect

    Morrison, H.; Lazar, R.; Haffner, G.D.; Whittle, D.M.; Gobas, F.A.P.C.

    1995-12-31

    A sub-model describing bioaccumulation and biomagnification in benthic invertebrates was incorporated into a steady-state food-web model (Gobas, 1993) was modified, to estimate concentrations of organic contaminants in aquatic organisms based on chemical concentrations in water and sediments. Model predictions were in good agreement with field data when applied to western Lake Erie. The improved ability of the model to simulate bioaccumulation by benthic invertebrates, makes this model particularly useful for quantifying contaminant transfer in the benthic food-web.

  15. Organic Contaminants in Riverine and Groundwater Systems: Aspects of the Anthropogenic Contribution

    NASA Astrophysics Data System (ADS)

    Schwarzbauer, Jan

    This book summarizes a selection of organic-geochemical investigations, which deal with the characterization and environmental behaviour of organic contaminations of German river and groundwater systems. The aim is to resume and present an overview of comprehensive current research activities, which have been published diversely in specialised scientific journals and, are therefore not easily available in a concise and clearly arranged way. Important topics include comprehensive non-target screening as well as isotope analysis of contaminants in water and sediments, detailed characterisation of bound residues, recording river ine pollution histories and an extensive application of the anthropogenic marker approach.

  16. [Methodological Approaches to the Organization of Counter Measures Taking into Account Landscape Features of Radioactively Contaminated Territories].

    PubMed

    Kuznetsov, V K; Sanzharova, N I

    2016-01-01

    Methodological approaches to the organization of counter measures are considered taking into account the landscape features of the radioactively contaminated territories. The current status and new requirements to the organization of counter measures in the contaminated agricultural areas are analyzed. The basic principles, objectives and problems of the formation of counter measures with regard to the landscape characteristics of the territory are presented; also substantiated are the organization and optimization of the counter measures in radioactively contaminated agricultural landscapes.

  17. [Methodological Approaches to the Organization of Counter Measures Taking into Account Landscape Features of Radioactively Contaminated Territories].

    PubMed

    Kuznetsov, V K; Sanzharova, N I

    2016-01-01

    Methodological approaches to the organization of counter measures are considered taking into account the landscape features of the radioactively contaminated territories. The current status and new requirements to the organization of counter measures in the contaminated agricultural areas are analyzed. The basic principles, objectives and problems of the formation of counter measures with regard to the landscape characteristics of the territory are presented; also substantiated are the organization and optimization of the counter measures in radioactively contaminated agricultural landscapes. PMID:27245009

  18. Unit Process Wetlands for Removal of Trace Organic Contaminants and Pathogens from Municipal Wastewater Effluents

    PubMed Central

    Jasper, Justin T.; Nguyen, Mi T.; Jones, Zackary L.; Ismail, Niveen S.; Sedlak, David L.; Sharp, Jonathan O.; Luthy, Richard G.; Horne, Alex J.; Nelson, Kara L.

    2013-01-01

    Abstract Treatment wetlands have become an attractive option for the removal of nutrients from municipal wastewater effluents due to their low energy requirements and operational costs, as well as the ancillary benefits they provide, including creating aesthetically appealing spaces and wildlife habitats. Treatment wetlands also hold promise as a means of removing other wastewater-derived contaminants, such as trace organic contaminants and pathogens. However, concerns about variations in treatment efficacy of these pollutants, coupled with an incomplete mechanistic understanding of their removal in wetlands, hinder the widespread adoption of constructed wetlands for these two classes of contaminants. A better understanding is needed so that wetlands as a unit process can be designed for their removal, with individual wetland cells optimized for the removal of specific contaminants, and connected in series or integrated with other engineered or natural treatment processes. In this article, removal mechanisms of trace organic contaminants and pathogens are reviewed, including sorption and sedimentation, biotransformation and predation, photolysis and photoinactivation, and remaining knowledge gaps are identified. In addition, suggestions are provided for how these treatment mechanisms can be enhanced in commonly employed unit process wetland cells or how they might be harnessed in novel unit process cells. It is hoped that application of the unit process concept to a wider range of contaminants will lead to more widespread application of wetland treatment trains as components of urban water infrastructure in the United States and around the globe. PMID:23983451

  19. Unit Process Wetlands for Removal of Trace Organic Contaminants and Pathogens from Municipal Wastewater Effluents.

    PubMed

    Jasper, Justin T; Nguyen, Mi T; Jones, Zackary L; Ismail, Niveen S; Sedlak, David L; Sharp, Jonathan O; Luthy, Richard G; Horne, Alex J; Nelson, Kara L

    2013-08-01

    Treatment wetlands have become an attractive option for the removal of nutrients from municipal wastewater effluents due to their low energy requirements and operational costs, as well as the ancillary benefits they provide, including creating aesthetically appealing spaces and wildlife habitats. Treatment wetlands also hold promise as a means of removing other wastewater-derived contaminants, such as trace organic contaminants and pathogens. However, concerns about variations in treatment efficacy of these pollutants, coupled with an incomplete mechanistic understanding of their removal in wetlands, hinder the widespread adoption of constructed wetlands for these two classes of contaminants. A better understanding is needed so that wetlands as a unit process can be designed for their removal, with individual wetland cells optimized for the removal of specific contaminants, and connected in series or integrated with other engineered or natural treatment processes. In this article, removal mechanisms of trace organic contaminants and pathogens are reviewed, including sorption and sedimentation, biotransformation and predation, photolysis and photoinactivation, and remaining knowledge gaps are identified. In addition, suggestions are provided for how these treatment mechanisms can be enhanced in commonly employed unit process wetland cells or how they might be harnessed in novel unit process cells. It is hoped that application of the unit process concept to a wider range of contaminants will lead to more widespread application of wetland treatment trains as components of urban water infrastructure in the United States and around the globe.

  20. Contamination of human ovarian follicular fluid and serum by chlorinated organic compounds in three Canadian cities.

    PubMed Central

    Jarrell, J F; Villeneuve, D; Franklin, C; Bartlett, S; Wrixon, W; Kohut, J; Zouves, C G

    1993-01-01

    OBJECTIVES: To determine the extent of contamination of ovarian follicular fluid and serum samples in women undergoing in-vitro fertilization and to study the effect of the contaminants on reproductive outcome. DESIGN: Inception cohort study. PATIENTS: Seventy-four women undergoing in-vitro fertilization at three regional clinics in Halifax, Hamilton, Ont., and Vancouver. MAIN OUTCOME MEASURES: Follicular fluid and serum levels of contaminants, cleavage rates and time to cleavage of first egg. RESULTS: Five chlorinated organic chemicals were frequently found in the two types of samples: alpha-chlordane (ALCH), dichlorochlorophenylethylene (DDE), heptachloroepoxide-oxychlordane (OXCH), hexachlorobenzene (HCB) and polychlorinated biphenyl (PCB). The levels were generally low. Regional differences between the three clinics were present. Samples from the Halifax clinic had the lowest frequency and level of contamination. The source of drinking water (well, bottled or municipal) was an important confounder. The concentrations of the five contaminants did not affect the cleavage rate or the time to cleavage of the first egg. CONCLUSION: Trace amounts of toxic and persistent chlorinated organic chemicals found in the follicular fluid of Canadian women undergoing in-vitro fertilization did not seem to have any adverse biologic effect on the rate of fertilization and the time to cleavage. Reasons for regional differences in the concentrations of contaminants require further study. PMID:8462054

  1. Do plants reflect atmospheric concentrations of persistent organic contaminants?

    SciTech Connect

    Jones, K.C.

    1994-12-31

    Chemical analysis of several types of plants -- such as pine needles, lichens, mosses and grasses -- has been used by numerous workers as a means of inferring spatial and temporal variations in the atmospheric concentrations of persistent organic compounds (e.g. PCBs, PAHs, CBs and PCDD/Fs). This is usually because plants are perceived as convenient `passive` air samplers and assumed to `integrate` variations in ambient concentrations during their lifetime. More recently, various researchers have sought to understand the mechanisms of exchange/uptake at the air vegetation surface, with a view to refining the use of vegetation sampling techniques and understanding the role of vegetation in influencing the global cycling of these compounds. This presentation will review some of the recent advances in this area, highlighting some of pitfalls and beneficial uses of employing plants as `monitoring tools`.

  2. Organic wastes to enhance phyto-treatment of diesel-contaminated soil.

    PubMed

    Dadrasnia, Arezoo; Agamuthu, P

    2013-11-01

    Toxic inorganic and organic chemicals are major contributors to environmental contamination and pose major health risks to human population. In this work, Dracaena reflexa and Podocarpus polystachyus were investigated for their potential to remove hydrocarbons from 2.5% and 1% diesel fuel-contaminated soil amended individually with 5% organic wastes (tea leaf, soy cake and potato skin) for a period of 270 days. Loss of 90% and 99% oil was recorded in soil contaminated with 2.5% and 1% oil with soy cake amendment, respectively, compared with 52% and 62% in unamended soil with D. reflexa at the end of 270 days. Similarly, 84% and 91% oil loss was recorded for P. polystachyus amended with organic wastes in 2.5% and 1% oil, respectively. Diesel fuel disappeared more rapidly in the soil amendment with SC than in other organic waste supplementation. It was evident that plants did not accumulate hydrocarbon from the soil, while the number of hydrocarbon-utilizing bacteria was high in the rhizosphere, thus suggesting that the mechanism of the oil degradation was rhizodegradation. The kinetic model result indicated a high rate of degradation in soil amendment with SC at 1% with D. reflexa compared with other treatments. Thus, a positive relationship was observed between diesel hydrocarbon degradation with plant biomass production. Dracaena reflexa with organic wastes amendment has a greater potential of restoring hydrocarbon-contaminated soil compared to P. polystachyus plant. PMID:24025373

  3. Selective removal of organic contaminants from sediments: A methodology for toxicity identification evaluations (TIEs)

    USGS Publications Warehouse

    Lebo, J.A.; Huckins, J.N.; Petty, J.D.; Ho, K.T.; Stern, E.A.

    2000-01-01

    Aqueous slurries of a test sediment spiked with dibenz[a,h]anthracene, 2,4,5,2',4',5'-hexachlorobiphenyl, p,p'-DDE, or phenanthrene were subjected to decontamination experimentation. The spiked sediments were agitated at elevated temperatures for at least 96 h in the presence of either of the two contaminant-absorbing media: clusters of polyethylene membrane or lipid- containing semipermeable membrane devices (SPMDs). The effects of treatment temperature and surface area of media on the removal of contaminants were explored. This work is part of a larger methodology for whole-sediment toxicity identification evaluation (TIE). A method is being sought that is capable of detoxifying sediments with respect to organic contaminants while leaving toxicity attributable to inorganic contaminants unaffected. (C) 2000 Elsevier Science Ltd.

  4. Contributions of contamination and organic enrichment to sediment toxicity near a sewage outfall

    SciTech Connect

    Bay, S.M.; Greenstein, D.J.

    1994-12-31

    Sediment and interstitial water toxicity and contamination were measured at 12 sites near the Los Angeles County Sanitation Districts sewage outfall on the Palos Verdes (Calif.) shelf, a region contaminated with many metal and organic contaminants. The spatial pattern of biological effects (sea urchin growth and fertilization) was compared with chemical concentrations in sediment, interstitial water, and gonad tissue to identify potentially meaningful relationships. Tissue analyses indicated that sediment metals were not bioavailable and therefore unlikely to be a significant factor in the sediment toxicity test responses. Sediment DDTs, PCBs, and PAHs were bioavailable and showed significant correlations with sea urchin growth effects. Interstitial water toxicity was most strongly correlated with measures of organic enrichment (hydrogen sulfide, ammonia) and hydrocarbon contamination. Subsequent dose response experiments confirmed the important role of hydrogen sulfide in interstitial water toxicity but failed to demonstrate an effect of DDE (the most abundant sediment organic contaminant) on growth. Overall, variations in measured sediment characteristics accounted for a relatively small portion of the biological responses.

  5. A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: Methodology and applications

    USGS Publications Warehouse

    Mahler, B.J.; Van Metre, P.C.

    2003-01-01

    Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We describe a simple, inexpensive methodology for the dewatering of sediment and present the results of two case studies. Isolation of a sufficient mass of sediment for analyses of organochlorine compounds and PAHs is obtained by in-line filtration of large volumes of water. The sediment is removed from the filters and analyzed directly by standard laboratory methods. In the first case study, suspended-sediment sampling was used to determine occurrence, loads, and yields of contaminants in urban runoff affecting biota in Town Lake, Austin, TX. The second case study used suspended-sediment sampling to locate a point source of PCBs in the Donna Canal in south Texas, where fish are contaminated with PCBs. The case studies demonstrate that suspended-sediment sampling can be an effective tool for determining the occurrence, load, and source of hydrophobic organic contaminants in transport.

  6. A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: methodology and applications.

    PubMed

    Mahler, B J; Van Metre, P C

    2003-04-01

    Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We describe a simple, inexpensive methodology for the dewatering of sediment and present the results of two case studies. Isolation of a sufficient mass of sediment for analyses of organochlorine compounds and PAHs is obtained by in-line filtration of large volumes of water. The sediment is removed from the filters and analyzed directly by standard laboratory methods. In the first case study, suspended-sediment sampling was used to determine occurrence, loads, and yields of contaminants in urban runoff affecting biota in Town Lake, Austin, TX. The second case study used suspended-sediment sampling to locate a point source of PCBs in the Donna Canal in south Texas, where fish are contaminated with PCBs. The case studies demonstrate that suspended-sediment sampling can be an effective tool for determining the occurrence, load, and source of hydrophobic organic contaminants in transport.

  7. A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: methodology and applications.

    PubMed

    Mahler, B J; Van Metre, P C

    2003-04-01

    Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We describe a simple, inexpensive methodology for the dewatering of sediment and present the results of two case studies. Isolation of a sufficient mass of sediment for analyses of organochlorine compounds and PAHs is obtained by in-line filtration of large volumes of water. The sediment is removed from the filters and analyzed directly by standard laboratory methods. In the first case study, suspended-sediment sampling was used to determine occurrence, loads, and yields of contaminants in urban runoff affecting biota in Town Lake, Austin, TX. The second case study used suspended-sediment sampling to locate a point source of PCBs in the Donna Canal in south Texas, where fish are contaminated with PCBs. The case studies demonstrate that suspended-sediment sampling can be an effective tool for determining the occurrence, load, and source of hydrophobic organic contaminants in transport. PMID:12712287

  8. Volatile organic silicon compounds: the most undesirable contaminants in biogases.

    PubMed

    Ohannessian, Aurélie; Desjardin, Valérie; Chatain, Vincent; Germain, Patrick

    2008-01-01

    Recently a lot of attention has been focused on volatile organic silicon compounds (VOSiC) present in biogases. They induce costly problems due to silicate formation during biogas combustion in valorisation engine. The cost of converting landfill gas and digester gas into electricity is adversely affected by this undesirable presence. VOSiC in biogases spark off formation of silicate deposits in combustion chambers. They engender abrasion of the inner surfaces leading to serious damage, which causes frequent service interruptions, thus reducing the economic benefit of biogases. It is already known that these VOSiC originate from polydimethylsiloxanes (PDMS) hydrolysis. PDMS (silicones) are used in a wide range of consumer and industrial applications. PDMS are released into the environment through landfills and wastewater treatment plants. There is a lack of knowledge concerning PDMS biodegradation during waste storage. Consequently, understanding PDMS behaviour in landfill cells and in sludge digester is particularly important. In this article, we focused on microbial degradation of PDMS through laboratory experiments. Preliminary test concerning anaerobic biodegradation of various PDMS have been investigated. Results demonstrate that the biotic step has an obvious influence on PDMS biodegradation. PMID:19029718

  9. Electrochemical Transformation of Trace Organic Contaminants in the Presence of Halide and Carbonate Ions

    PubMed Central

    2016-01-01

    Electrochemical treatment on anodes shows promise for the oxidation of organic contaminants in industrial wastewater and reverse osmosis concentrate from municipal wastewater recycling due to the high conductivity of the matrix and the concomitant low energy demand. The effect of background electrolyte composition (Cl–, HCO3–, and NH4+) on the formation and fate of electrochemically produced heterogeneous (HO•ads and Cl•ads) and homogeneous (HOCl and HOBr) oxidants was evaluated on Ti–IrO2 and boron-doped diamond (BDD) electrodes using a suite of trace organic contaminants that exhibited varying reactivity with HO•, CO3•–, HOCl, and HOBr. The contributions of adsorbed and bulk oxidants to contaminant degradation were investigated. Results show that transformation rates for most contaminants increased in the presence of chloride and trace amounts of bromide; however, elevated concentrations of HCO3– often altered transformation rates due to formation of selective oxidants, with decreases in reactivity observed for electron-poor contaminants and increases in reactivity observed for compounds with amine and phenolic moieties. Using this information, rates of reactions on anode surfaces and measured production and loss rates for reactive homogeneous species were used to predict contaminant removal in municipal wastewater effluent. Despite some uncertainty in the reaction mechanisms, the model accurately predicted rates of removal of electron-rich contaminants but underestimated the transformation rates of compounds that exhibited low reactivity with HOCl and HOBr, possibly due to the formation of halogen radicals. The approach employed in this study provides a means of identifying key reactions for different classes of contaminants and for predicting the conditions under which anodic treatment of wastewater will be practical. PMID:27599127

  10. Electrochemical Transformation of Trace Organic Contaminants in the Presence of Halide and Carbonate Ions.

    PubMed

    Barazesh, James M; Prasse, Carsten; Sedlak, David L

    2016-09-20

    Electrochemical treatment on anodes shows promise for the oxidation of organic contaminants in industrial wastewater and reverse osmosis concentrate from municipal wastewater recycling due to the high conductivity of the matrix and the concomitant low energy demand. The effect of background electrolyte composition (Cl(-), HCO3(-), and NH4(+)) on the formation and fate of electrochemically produced heterogeneous (HO(•)ads and Cl(•)ads) and homogeneous (HOCl and HOBr) oxidants was evaluated on Ti-IrO2 and boron-doped diamond (BDD) electrodes using a suite of trace organic contaminants that exhibited varying reactivity with HO(•), CO3(•-), HOCl, and HOBr. The contributions of adsorbed and bulk oxidants to contaminant degradation were investigated. Results show that transformation rates for most contaminants increased in the presence of chloride and trace amounts of bromide; however, elevated concentrations of HCO3(-) often altered transformation rates due to formation of selective oxidants, with decreases in reactivity observed for electron-poor contaminants and increases in reactivity observed for compounds with amine and phenolic moieties. Using this information, rates of reactions on anode surfaces and measured production and loss rates for reactive homogeneous species were used to predict contaminant removal in municipal wastewater effluent. Despite some uncertainty in the reaction mechanisms, the model accurately predicted rates of removal of electron-rich contaminants but underestimated the transformation rates of compounds that exhibited low reactivity with HOCl and HOBr, possibly due to the formation of halogen radicals. The approach employed in this study provides a means of identifying key reactions for different classes of contaminants and for predicting the conditions under which anodic treatment of wastewater will be practical. PMID:27599127

  11. Development and field testing of Teen Pocket PATH(®), a mobile health application to improve medication adherence in adolescent solid organ recipients.

    PubMed

    Shellmer, Diana A; Dew, Mary Amanda; Mazariegos, George; DeVito Dabbs, Annette

    2016-02-01

    Applying principles of user-centered design, we iteratively developed and tested the prototype of TPP, an mHealth application to promote medication adherence and enhance communication about medication management between adolescents and primary caregivers. A purposive sample of seven adolescent solid organ transplant recipients who were ≥ one yr post-transplant and their primary caregivers participated. Participants completed up to three face-to-face laboratory usability sessions, a 6-week field test, and a debriefing session. Primary caregivers participated in an additional usability telephone session. Participants completed usability and satisfaction measures. Sample included liver (n = 4), heart (n = 2), and lung (n = 1) recipients aged 11-18 yr (57% were female, 86% were Caucasian), and nine primary caregivers aged 42-61 yr (88.9% were parents, 88% were female, 88% were Caucasian). Ninety percent of the adolescents endorsed the graphs or logs of missed/late medication dosing as useful and 100% endorsed the remaining features (e.g., medication list, dose time reminders/warnings) as useful. All adolescents expressed interest in using TPP for monitoring medications and satisfaction with the automatic messaging between adolescent and caregiver versions of the application. Adolescents unanimously found TPP easy to use. TPP shows promise as an mHealth adherence tool.

  12. [Solute transport modeling application in groundwater organic contaminant source identification].

    PubMed

    Wang, Shu-Fang; Wang, Li-Ya; Wang, Xiao-Hong; Lin, Pei; Liu, Jiu-Rong; Xin, Bao-Dong; He, Guo-Ping

    2012-03-01

    Investigation and numerical simulation, based on RT3D (reactive transport in 3-dimensions)were used to identify the source of tetrachloroethylene (PCE) and trichloroethylene (TCE) in the groundwater of a city in the north of China and reverse the input intensity. Multiple regressions were applied to analyze the influenced factors of input intensity of PCE and TCE using Stepwise function in Matlab. The results indicate that the factories and industries are the source of the PCE and TCE in groundwater. Natural attenuation was identified and the natural attenuation rates are 93.15%, 61.70% and 61.00% for PCE, and 70.05%, 73.66% and 63.66% for TCE in 173 days. The 4 source points identified by the simulation have released 0.910 6 kg PCE and 95.693 8 kg TCE during the simulation period. The regression analysis results indicate that local precipitation and the thickness of vadose zone are the main factors influencing organic solution transporting from surface to groundwater. The PCE and TCE concentration are found to be 0 and 5 mg x kg(-1) from surface to 35 cm in vadose zone. All above results suggest that PCE and TCE in groundwater are from the source in the surface. Natural attenuation occurred when PCE and TCE transporting from the surface to groundwater, and the rest was transported to groundwater through vadose zone. Local precipitation was one of the critical factors influencing the transportation of PCE and TCE to aquifer through sand, pebble and gravel of the Quaternary.

  13. The delivery of organic contaminants to the Arctic food web: why sea ice matters.

    PubMed

    Pućko, Monika; Stern, Gary A; Macdonald, Robie W; Jantunen, Liisa M; Bidleman, Terry F; Wong, Fiona; Barber, David G; Rysgaard, Søren

    2015-02-15

    For decades sea ice has been perceived as a physical barrier for the loading of contaminants to the Arctic Ocean. We show that sea ice, in fact, facilitates the delivery of organic contaminants to the Arctic marine food web through processes that: 1) are independent of contaminant physical-chemical properties (e.g. 2-3-fold increase in exposure to brine-associated biota), and 2) depend on physical-chemical properties and, therefore, differentiate between contaminants (e.g. atmospheric loading of contaminants to melt ponds over the summer, and their subsequent leakage to the ocean). We estimate the concentrations of legacy organochlorine pesticides (OCPs) and current-use pesticides (CUPs) in melt pond water in the Beaufort Sea, Canadian High Arctic, in 2008, at near-gas exchange equilibrium based on Henry's law constants (HLCs), air concentrations and exchange dynamics. CUPs currently present the highest risk of increased exposures through melt pond loading and drainage due to the high ratio of melt pond water to seawater concentration (Melt pond Enrichment Factor, MEF), which ranges from 2 for dacthal to 10 for endosulfan I. Melt pond contaminant enrichment can be perceived as a hypothetical 'pump' delivering contaminants from the atmosphere to the ocean under ice-covered conditions, with 2-10% of CUPs annually entering the Beaufort Sea via this input route compared to the standing stock in the Polar Mixed Layer of the ocean. The abovementioned processes are strongly favored in first-year ice compared to multi-year ice and, therefore, the dynamic balance between contaminant inventories and contaminant deposition to the surface ocean is being widely affected by the large-scale icescape transition taking place in the Arctic. PMID:25437762

  14. The delivery of organic contaminants to the Arctic food web: why sea ice matters.

    PubMed

    Pućko, Monika; Stern, Gary A; Macdonald, Robie W; Jantunen, Liisa M; Bidleman, Terry F; Wong, Fiona; Barber, David G; Rysgaard, Søren

    2015-02-15

    For decades sea ice has been perceived as a physical barrier for the loading of contaminants to the Arctic Ocean. We show that sea ice, in fact, facilitates the delivery of organic contaminants to the Arctic marine food web through processes that: 1) are independent of contaminant physical-chemical properties (e.g. 2-3-fold increase in exposure to brine-associated biota), and 2) depend on physical-chemical properties and, therefore, differentiate between contaminants (e.g. atmospheric loading of contaminants to melt ponds over the summer, and their subsequent leakage to the ocean). We estimate the concentrations of legacy organochlorine pesticides (OCPs) and current-use pesticides (CUPs) in melt pond water in the Beaufort Sea, Canadian High Arctic, in 2008, at near-gas exchange equilibrium based on Henry's law constants (HLCs), air concentrations and exchange dynamics. CUPs currently present the highest risk of increased exposures through melt pond loading and drainage due to the high ratio of melt pond water to seawater concentration (Melt pond Enrichment Factor, MEF), which ranges from 2 for dacthal to 10 for endosulfan I. Melt pond contaminant enrichment can be perceived as a hypothetical 'pump' delivering contaminants from the atmosphere to the ocean under ice-covered conditions, with 2-10% of CUPs annually entering the Beaufort Sea via this input route compared to the standing stock in the Polar Mixed Layer of the ocean. The abovementioned processes are strongly favored in first-year ice compared to multi-year ice and, therefore, the dynamic balance between contaminant inventories and contaminant deposition to the surface ocean is being widely affected by the large-scale icescape transition taking place in the Arctic.

  15. Organic containment separator

    DOEpatents

    Del Mar, Peter

    1995-01-01

    A process of sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium by (a) passing an initial aqueous medium including a minor amount of the organic contaminant through a composite tube including a polymeric base material selected from the group of polyolefins and polyfluorocarbons and particles of a carbon allotrope material adfixed to the inner wall of the polymeric base material, the composite tube having an internal diameter of from about 0.1 to about 2.0 millimeters and being of sufficient length to permit the organic contaminant to adhere to the composite tube, (b) passing a solvent through the composite tube, said solvent capable of separating the adhered organic contaminant from the composite tube. Further, an extraction apparatus for sample preparation prior to analysis for the concentration of an organic contaminant in an aqueous medium, said apparatus including a composite tube including a polymeric base material selected from the group of polyolefins and polyfluorocarbons and particles of a carbon allotrope material adfixed to the inner wall of the polymeric base material, the composite tube having an internal diameter of from about 0.1 to about 2.0 millimeters and being of sufficient length to permit an organic contaminant contained within an aqueous medium passed therethrough to adhere to the composite tube is disclosed.

  16. Characterization of organic chemical contaminants in sediments from Jobos Bay, Puerto Rico.

    PubMed

    Pait, Anthony S; Whitall, David R; Dieppa, Angel; Newton, Sarah E; Brune, Lia; Caldow, Chris; Mason, Andrew L; Apeti, Dennis A; Christensen, John D

    2012-08-01

    Jobos Bay, located on the southeastern coast of Puerto Rico, contains a variety of habitats including mangroves, seagrass meadows, and coral reefs. The watershed surrounding the bay includes a number of towns, agricultural areas, and the Jobos Bay National Estuarine Research Reserve (NERR). Jobos Bay and the surrounding watershed are part of a Conservation Effects Assessment Project (CEAP), involving the Jobos Bay NERR, the US Department of Agriculture, and the National Oceanic and Atmospheric Administration (NOAA) to assess the benefits of agricultural best management practices (BMPs) on the terrestrial and marine environments. As part of the Jobos Bay CEAP, NOAA collected sediment samples in May 2008 to characterize over 130 organic chemical contaminants. This paper presents the results of the organic contaminant analysis. The organic contaminants detected in the sediments included polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, and the pesticide DDT. PAHs at one site in the inner bay near a boat yard were significantly elevated; however, all organic contaminant classes measured were below NOAA sediment quality guidelines that would have indicated that impacts were likely. The results of this work provide an important baseline assessment of the marine environment that will assist in understanding the benefits of implementing BMPs on water quality in Jobos Bay.

  17. Organic Contaminant Levels in Three Fish Species Downchannel from the Los Alamos National Laboratory

    SciTech Connect

    Gonzales, G.J.; Fresquez, P.R.; Beveridge, J.W.

    1999-06-01

    The LANL contribution, if any, to organic contaminant levels in the common carp, the channel catfish, and the white sucker in the Rio Grande appear to be small; however, low sample sizes, high variation, and potential interaction of species effect with location treatment effect require additional sampling and analysis.

  18. Identifying sources of emerging organic contaminants in a mixed use watershed using principal components analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Principal components analysis (PCA) was used to identify sources of emerging organic contaminants in the Zumbro River watershed in southeastern Minnesota. Two main principal components (PCs) were identified, which together explained more than 50% of the variance in the data. Principal Component 1 (P...

  19. USING GENOMICS AND PROTEOMICS TO DIAGNOSE EXPOSURE OF AQUATIC ORGANISMS TO ENVIRONMENTAL CONTAMINANTS

    EPA Science Inventory

    Advances in molecular biology allow the use of cutting-edge genomic and proteomic tools to assess the effects of environmental contaminants on aquatic organisms. Techniques are available to measure changes in expression of single genes (quantitative real-time PCR) or to measure g...

  20. Characterization of organic chemical contaminants in sediments from Jobos Bay, Puerto Rico.

    PubMed

    Pait, Anthony S; Whitall, David R; Dieppa, Angel; Newton, Sarah E; Brune, Lia; Caldow, Chris; Mason, Andrew L; Apeti, Dennis A; Christensen, John D

    2012-08-01

    Jobos Bay, located on the southeastern coast of Puerto Rico, contains a variety of habitats including mangroves, seagrass meadows, and coral reefs. The watershed surrounding the bay includes a number of towns, agricultural areas, and the Jobos Bay National Estuarine Research Reserve (NERR). Jobos Bay and the surrounding watershed are part of a Conservation Effects Assessment Project (CEAP), involving the Jobos Bay NERR, the US Department of Agriculture, and the National Oceanic and Atmospheric Administration (NOAA) to assess the benefits of agricultural best management practices (BMPs) on the terrestrial and marine environments. As part of the Jobos Bay CEAP, NOAA collected sediment samples in May 2008 to characterize over 130 organic chemical contaminants. This paper presents the results of the organic contaminant analysis. The organic contaminants detected in the sediments included polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, and the pesticide DDT. PAHs at one site in the inner bay near a boat yard were significantly elevated; however, all organic contaminant classes measured were below NOAA sediment quality guidelines that would have indicated that impacts were likely. The results of this work provide an important baseline assessment of the marine environment that will assist in understanding the benefits of implementing BMPs on water quality in Jobos Bay. PMID:21956337

  1. Partitioning of Organic Contaminants and Tracer Compounds in a CO2-Brine System at High Salinities

    NASA Astrophysics Data System (ADS)

    Thomas, B.; Kharaka, Y. K.; Rosenbauer, R. J.; Janesko, D.; Trutna, J.

    2011-12-01

    Nonionic chemical species including gases and organic compounds partition between the fluid CO2 phase and the aqueous phase in geologic carbon sequestration systems. The injection and migration of CO2 in geologic carbon sequestration systems covers a wide range of pressure and temperature, so it is important to understand the partitioning of these compounds at various P-T conditions and salinities. Geochemical data is particularly lacking for the partitioning of organic contaminant compounds and tracer compounds between highly saline brines and CO2. Most groundwater is relatively low in organic contaminants; however, groundwater associated with hydrocarbon migration pathways, enhanced oil recovery (EOR), and hydrocarbon storage or extraction can contain high concentrations of known organic contaminants. CO2 injection in these systems may therefore be more likely to result in partitioning of contaminants into the CO2 phase that could, upon migration, represent an important risk to groundwater resources. We present the experimental apparatus and determination of partition coefficients between brine and CO2 for a suite of compounds including benzene, toluene, ethylbenzene, xylene (BTEX), and low molecular weight polynuclear aromatic hydrocarbons (PAHs). In addition, partition coefficients are determined for the important gas phase tracer compounds: SF6 and Krypton covering a P-T envelope consistent with CO2 injection and plume migration to the near surface.

  2. Organic contaminant release from melting snow. 2. Influence of snow pack and melt characteristics.

    PubMed

    Meyer, Torsten; Lei, Ying Duan; Muradi, Ibrahim; Wania, Frank

    2009-02-01

    Large reservoirs of organic contaminants in seasonal snowpack can be released in short pulses during spring snowmelt, potentially impacting the receiving ecosystems. Laboratory experiments using artificial snow spiked with organic target substances were conducted to investigate the behavior of six organic contaminants with widely variable distribution properties in melting snow. Whereas the influence of a chemical's equilibrium phase partitioning on the elution behavior is explored in a companion paper, we discuss here the impact of snow properties and melt features, including the snowpack depth, the temperature at the interface between soil and snow, the meltwater content the internal ice surface area, and the existence of distinct snow layers. Water-soluble organic substances are released in high concentrations at the beginning of a melt period when a deep and aged snowpack undergoes intense melting. Warm ground can cause notable melting at the snow bottom leading to a delayed and dampened concentration peak. Hydraulic barriers in layered snow packs cause preferential meltwater flow which also mitigates the early contaminant flush. Hydrophobic organic pollutants that are associated with particles accumulate near the snow surface and are released at the end of melting. Dirt cones at the surface of a dense snowpack enhance this enrichment. The findings of this laboratory study will aid in the understanding of the behavior of organic pollutants during the melting of more complex, natural snow covers.

  3. Organic contaminant release from melting snow. 2. Influence of snow pack and melt characteristics.

    PubMed

    Meyer, Torsten; Lei, Ying Duan; Muradi, Ibrahim; Wania, Frank

    2009-02-01

    Large reservoirs of organic contaminants in seasonal snowpack can be released in short pulses during spring snowmelt, potentially impacting the receiving ecosystems. Laboratory experiments using artificial snow spiked with organic target substances were conducted to investigate the behavior of six organic contaminants with widely variable distribution properties in melting snow. Whereas the influence of a chemical's equilibrium phase partitioning on the elution behavior is explored in a companion paper, we discuss here the impact of snow properties and melt features, including the snowpack depth, the temperature at the interface between soil and snow, the meltwater content the internal ice surface area, and the existence of distinct snow layers. Water-soluble organic substances are released in high concentrations at the beginning of a melt period when a deep and aged snowpack undergoes intense melting. Warm ground can cause notable melting at the snow bottom leading to a delayed and dampened concentration peak. Hydraulic barriers in layered snow packs cause preferential meltwater flow which also mitigates the early contaminant flush. Hydrophobic organic pollutants that are associated with particles accumulate near the snow surface and are released at the end of melting. Dirt cones at the surface of a dense snowpack enhance this enrichment. The findings of this laboratory study will aid in the understanding of the behavior of organic pollutants during the melting of more complex, natural snow covers. PMID:19244999

  4. Partitioning microbial respiration between jet fuel and native organic matter in an organic-rich long time-contaminated aquifer.

    PubMed

    Bugna, G C; Chanton, J P; Stauffer, T B; MacIntyre, W G; Libelo, E L

    2005-07-01

    The relative importance of jet fuel biodegradation relative to the respiration of natural organic matter in a contaminated organic-rich aquifer underlying a fire training area at Tyndall Air Force Base, Florida, USA was determined with isotopic measurements. Thirteen wells were sampled and analyzed for BTX (benzene, toluene, xylene), dissolved inorganic carbon (DIC) and CH4 concentrations, and delta13C and 14C of DIC. Results range from non-detectable to 3790 ppb, 1.4-24 mM, 0.2-776 microM, +5.8 per thousand to -22 per thousand, and from 52 to 99 pmc, respectively. Residual fuel was confined to two center wells underlying the fire training area. DIC and CH4 concentrations were elevated down-gradient of the contamination, but also at sites that were not in the apparent flow path of the contaminated groundwater. DIC exhibited greatest delta13C enrichment at highest DIC and CH4 concentrations indicating that CH4 production was an important respiration mode. Radiocarbon-depleted DIC was observed at sites with high hydrocarbon concentrations and down-gradient of the site. The results indicate that while natural attenuation was not rapidly reducing the quantity of free product overlying the aquifer at the site of contamination, it was at least constraining its flow away from the spill site. Apparently under the conditions of this study, BTX was degraded as rapidly as it was dissolved.

  5. Mass Spectrum Analysis of Gas Emitted during Organic Contaminant Removal from a Metal Surface with an Arc in Low Vacuum

    SciTech Connect

    Sugimoto, Masaya; Takeda, Koichi

    2006-05-05

    The gas emitted during organic contaminant removal from a metal surface with an arc in low vacuum is investigated using a quadrupole mass spectrometer. The experimental results show that fragment molecules of the contaminant material, which are created by the decomposition of the contaminant material, exist in the emitted gas. The decomposition rate of the contaminant increased with the treatment current, which indicates that the decomposition occurs not in the cathode spot, but in the arc column.

  6. Evidence of Maternal Offloading of Organic Contaminants in White Sharks (Carcharodon carcharias)

    PubMed Central

    Mull, Christopher G.; Lyons, Kady; Blasius, Mary E.; Winkler, Chuck; O’Sullivan, John B.; Lowe, Christopher G.

    2013-01-01

    Organic contaminants were measured in young of the year (YOY) white sharks (Carcharodon carcharias) incidentally caught in southern California between 2005 and 2012 (n = 20) and were found to be unexpectedly high considering the young age and dietary preferences of young white sharks, suggesting these levels may be due to exposure in utero. To assess the potential contributions of dietary exposure to the observed levels, a five-parameter bioaccumulation model was used to estimate the total loads a newborn shark would potentially accumulate in one year from consuming contaminated prey from southern California. Maximum simulated dietary accumulation of DDTs and PCBs were 25.1 and 4.73 µg/g wet weight (ww) liver, respectively. Observed ΣDDT and ΣPCB concentrations (95±91 µg/g and 16±10 µg/g ww, respectively) in a majority of YOY sharks were substantially higher than the model predictions suggesting an additional source of contaminant exposure beyond foraging. Maternal offloading of organic contaminants during reproduction has been noted in other apex predators, but this is the first evidence of transfer in a matrotrophic shark. While there are signs of white shark population recovery in the eastern Pacific, the long-term physiological and population level consequences of biomagnification and maternal offloading of environmental contaminants in white sharks is unclear. PMID:23646154

  7. Exposure assessment of environmental organic chemicals at contaminated sites: a multicompartment modelling approach.

    PubMed

    Matthies, M

    2003-04-11

    For the prevention of future damages from chemicals at large contaminated sites, all transfer pathways leading to the exposure of man and vulnerable ecosystems have to be taken into account. For organic contaminants, the uptake into vegetation is the major entry route for the transfer into the food chains. Lipophilic substances are taken up by roots but are not translocated with the transpiration stream. Atmospheric background concentrations have a significant impact on foliage contamination due to the effective gaseous and particle deposition. Vegetables can also be contaminated after irrigation with contaminated water supplied by groundwater wells. By means of a multicompartment model, the various uptake processes into roots and foliage as well as the transformation and translocation processes are described and the concentration pattern resulting from daily irrigation with methyl-t-butyl ether in the edible parts is simulated. The results demonstrate the advantage of a dynamic multicompartment model over the static environmental quality standard approach in terms of derivation of possible exposure reduction measures for organic chemicals.

  8. Two-stage bioreactor to destroy chlorinated and nonchlorinated organic groundwater contaminants

    SciTech Connect

    Folsom, B.R.; Bohner, A.K.; Burick, T.; Guarini, W.J.

    1995-12-31

    Both chlorinated and nonchlorinated volatile organic compounds are found as common contaminants of groundwater across the nation. Two field-pilot bioreactors successfully treated contaminated groundwater at Robins Air Force Base (AFB). The fluidized-bed bioreactor (FBR) effectively removed >97% of the 1,2-dichlorobenzene (DCB) and >95% of the benzene, toluene, ethylbenzene, and xylene(s) (BTEX) from more than 210,000 gal of contaminated groundwater. The FBR removed 84% of the trichloroethylene (TCE), also found in this groundwater, based on a total mass balance beyond carbon adsorption. Enhanced operational stability was demonstrated for the gas-phase reactor (GPR) with 10 months of continuous operation in the laboratory and 2 months in the field. TCE concentrations in contaminated air entering the pilot GPR were reduced by 75% on average. Capital and operating costs for the FBR system were compared to other treatment options including ultraviolet (UV)-peroxidation, air stripping with carbon adsorption, and wet carbon adsorption. GPR economics were compared to carbon adsorption at two TCE concentrations. These bioreactor systems provide economical, destructive technologies for treating either contaminated water or contaminated air originating from air stripping, air sparging, or soil vapor extraction operations and will be effective remedial options at many sites.

  9. Advances in Dynamic Transport of Organic Contaminants in Karst Groundwater Systems

    NASA Astrophysics Data System (ADS)

    Padilla, I. Y.; Vesper, D.; Alshawabkeh, A.; Hellweger, F.

    2011-12-01

    Karst groundwater systems develop in soluble rocks such as limestone, and are characterized by high permeability and well-developed conduit porosity. These systems provide important freshwater resources for human consumption and ecological integrity of streams, wetlands, and coastal zones. The same characteristics that make karst aquifers highly productive make them highly vulnerable to contamination. As a result, karst aquifers serve as an important route for contaminants exposure to humans and wildlife. Transport of organic contaminants in karst ground-water occurs in complex pathways influenced by the flow mechanism predominating in the aquifer: conduit-flow dominated systems tend to convey solutes rapidly through the system to a discharge point without much attenuation; diffuse-flow systems, on the other hand, can cause significant solute retardation and slow movement. These two mechanisms represent end members of a wide spectrum of conditions found in karst areas, and often a combination of conduit- and diffuse-flow mechanisms is encountered, where both flow mechanisms can control the fate and transport of contaminants. This is the case in the carbonate aquifers of northern Puerto Rico. This work addresses advances made on the characterization of fate and transport processes in karst ground-water systems characterized by variable conduit and/or diffusion dominated flow under high- and low-flow conditions. It involves laboratory-scale physical modeling and field-scale sampling and historical analysis of contaminant distribution. Statistical analysis of solute transport in Geo-Hydrobed physical models shows the heterogeneous character of transport dynamics in karstic units, and its variability under different flow regimes. Field-work analysis of chlorinated volatile organic compounds and phthalates indicates a large capacity of the karst systems to store and transmit contaminants. This work is part of the program "Puerto Rico Testsite for Exploring Contamination

  10. [Arbuscular mycorrhizal bioremediation and its mechanisms of organic pollutants-contaminated soils].

    PubMed

    Li, Qiuling; Ling, Wanting; Gao, Yanzheng; Li, Fuchun; Xiong, Wei

    2006-11-01

    Arbuscular mycorrhiza (AM), the symbiont of arbuscular mycorrhizal fungi (AMF) and host plant root, has been proved to be able to improve soil structure and enhance the plant resistance to environmental stress. There are more than 170 kinds of AMF worldwide. Recently, the promoted degradation of organic pollutants in soils in the presence of AM was observed, and AM bioremediation (AMB) is becoming a promising and perspective remediation technique for organic pollutants-contaminated soils. This paper reviewed the research progress on the AMB of soils contaminated by typical organic pollutants such as polycyclic aromatic hydrocarbons, PAEs, petroleum, and pesticides. The mechanisms of AMB mainly include the metabolism of organic pollutants by AM fungi, the degradation of these pollutants by the enzymes derived from AM exudation and by the enhanced root exudation and rhizospheric microbial activity in the presence of AM, and the removal of the pollutants by plant uptake and accumulation. As a new approach for the remediation of contaminated soils, some aspects involved in AMB, e.g., the screening of high efficient AM fungi, efficacy of co-existing AM fungi, soil ageing, and plant uptake of organic pollutants from soils in the presence of AM, still need to be further investigated.

  11. Assessing the bioaccumulation of contaminants from sediments by fish and other aquatic organisms

    USGS Publications Warehouse

    Willford, Wayne A.; Mac, Michael J.; Hesselberg, Robert J.

    1987-01-01

    Contaminated sediments that are not acutely toxic to aquatic organisms but contain bioaccumulable toxic substances present a common, yet poorly understood problem for regulatory decision makers. In order to recommend options to minimize bioaccumulation of these toxic substances, decisionmakers need estimates of 1. which substances are available for accumulation by aquatic organisms; and 2. the potential impacts of such accumulation. The most direct and meaningful approach to estimating bioavailability is measurement of contaminant uptake by aquatic organisms exposed to the sediments of concern. Reasonably reliable methodologies exist for performing such exposures in the laboratory and in situ using marine or freshwater organisms. Such methods can demonstrate short-term potential for bioaccumulation of toxics from the sediments, but not necessarily the biological significance or long-term impact of any accumulated residues in the organisms and transfer of those residues through the food chain. Since most contaminated sediments contain a mixture of toxic substances, determination of the biological significance of their accumulation is not likely in the near future. Thus, the direct measurement of significant bioaccumulation of toxic substances from the sediments remains the most immediately useful index in a decision-making process.

  12. Organic contamination of ground water at Gas Works Park, Seattle, Washington

    USGS Publications Warehouse

    Turney, G.L.; Goerlitz, D.F.

    1990-01-01

    Gas Works Park, in Seattle, Washington, is located on the site of a coal and oil gasification plant that ceased operation in 1956. During operation, many types of wastes, including coal, tar, and oil, accumulated on-site. The park soil is currently (1986) contaminated with compounds such as polynuclear aromatic hydrocarbons, volatile organic compounds, trace metals, and cyanide. Analyses of water samples from a network of observation wells in the park indicate that these compounds are also present in the ground water. Polynuclear aromatic hydrocarbons and volatile organic compounds were identified in ground water samples in concentrations as large as 200 mg/L. Concentrations of organic compounds were largest where ground water was in contact with a non-aqueous phase liquid in the soil. Where no non-aqueous phase liquid was present, concentrations were much smaller, even if the ground water was in contact with contaminated soils. This condition is attributed to weathering processes in which soluble, low-molecular-weight organic compounds are preferentially dissolved from the non-aqueous phase liquid into the ground water. Where no non-aqueous phase liquid is present, only stained soils containing relatively insoluble, high-molecular-weight compounds remain. Concentrations of organic contaminants in the soils may still remain large.

  13. The effect of organic contaminants on the spectral induced polarization response of porous media - mechanistic approach

    NASA Astrophysics Data System (ADS)

    Schwartz, N.; Huisman, J. A.; Furman, A.

    2012-12-01

    In recent years, there is a growing interest in using geophysical methods in general and spectral induced polarization (SIP) in particular as a tool to detect and monitor organic contaminants within the subsurface. The general idea of the SIP method is to inject alternating current through a soil volume and to measure the resultant potential in order to obtain the relevant soil electrical properties (e.g. complex impedance, complex conductivity/resistivity). Currently, a complete mechanistic understanding of the effect of organic contaminants on the SIP response of soil is still absent. In this work, we combine laboratory experiments with modeling to reveal the main processes affecting the SIP signature of soil contaminated with organic pollutant. In a first set of experiments, we investigate the effect of non-aqueous phase liquids (NAPL) on the complex conductivity of unsaturated porous media. Our results show that addition of NAPL to the porous media increases the real component of the soil electrical conductivity and decreases the polarization of the soil (imaginary component of the complex conductivity). Furthermore, addition of NAPL to the soil resulted in an increase of the electrical conductivity of the soil solution. Based on these results, we suggest that adsorption of NAPL to the soil surface, and exchange process between polar organic compounds in the NAPL and inorganic ions in the soil are the main processes affecting the SIP signature of the contaminated soil. To further support our hypothesis, the temporal change of the SIP signature of a soil as function of a single organic cation concentration was measured. In addition to the measurements of the soil electrical properties, we also measured the effect of the organic cation on the chemical composition of both the bulk and the surface of the soil. The results of those experiments again showed that the electrical conductivity of the soil increased with increasing contaminant concentration. In addition

  14. Compositional Effects on Interfacial Properties in Contaminated Systems: Implications for Organic Liquid Migration and Recovery

    SciTech Connect

    Abriola, Linda M.; Demond, Avery H.; Hsu, Hsin-lan; O'Carroll, Denis M.; Phelan, Thoams, J.; Polityka, Catherine A.; Ryder, Jodi L.

    2003-03-27

    An understanding of the transport behavior of dense non-aqueous phase organic liquids (DNAPLs) is a prerequisite for the accurate assessment of chemical exposure and the design of effective subsurface remediation strategies. This paper highlights results of an ongoing EMSP research project designed to explore the influence of solid and organic phase composition on DNAPL migration, entrapment and recovery from contaminated aquifers. The integrated research program includes small-scale laboratory investigations to examine the dependence of organic contaminant constitutive relationships (e.g., capillary pressure-saturation, relative permeability, residual saturation and interphase mass transfer rates) on interfacial properties. Models developed from these observations are being incorporated into a compositional multiphase simulator to facilitate prediction of DNAPL behavior under conditions representative of field sites. Two-dimensional sand box experiments are also being undertaken to validate the modeling approach. Results from this research demonstrate the dramatic influence of interfacial property variation on DNAPL migration and retention.

  15. Development of a passive, in situ, integrative sampler for hydrophilic organic contaminants in aquatic environments

    USGS Publications Warehouse

    Alvarez, D.A.; Petty, J.D.; Huckins, J.N.; Jones-Lepp, T. L.; Getting, D.T.; Goddard, J.P.; Manahan, S.E.

    2004-01-01

    Increasingly it is being realized that a holistic hazard assessment of complex environmental contaminant mixtures requires data on the concentrations of hydrophilic organic contaminants including new generation pesticides, pharmaceuticals, personal care products, and many chemicals associated with household, industrial, and agricultural wastes. To address this issue, we developed a passive in situ sampling device (the polar organic chemical integrative sampler [POCIS]) that integratively concentrates trace levels of complex mixtures of hydrophilic environmental contaminants, enables the determination of their time-weighted average water concentrations, and provides a method of estimating the potential exposure of aquatic organisms to the complex mixture of waterborne contaminants. Using a prototype sampler, linear uptake of selected herbicides and pharmaceuticals with log Kows < 4.0 was observed for up to 56 d. Estimation of the ambient water concentrations of chemicals of interest is achieved by using appropriate uptake models and determination of POCIS sampling rates for appropriate exposure conditions. Use of POCIS in field validation studies targeting the herbicide diuron in the United Kingdom resulted in the detection of the chemical at estimated concentrations of 190 to 600 ng/L. These values are in agreement with reported levels found in traditional grab samples taken concurrently.

  16. Applying membrane technology to air stripping effluent for remediation of groundwater contaminated with volatile organic compounds

    SciTech Connect

    Brown, J.J.; Erickson, M.D.; Beskid, N.J.

    1993-12-31

    Remediation groundwater contaminated by volatile organic compounds (VOCs) requires cost- and technically-effective solutions. This paper reviews the options for VOC removal from remediation air streams, focusing on membrane separation. The basic separation science and technology, results of performance tests, and results of cost studies for membrane separation are presented. Competing technologies are discussed and compared with membrane separation. Membrane separation combined with air stripping will provide an economically and environmentally safe technology for remediation of VOC-contaminated groundwater and, as it matures, may become the preferred method. 9 refs., 6 figs., 2 tabs.

  17. Microbiological Analysis of an Active Pilot-Scale Mobile Bioreactor Treating Organic Contaminants

    SciTech Connect

    Brigmon, R.L.

    1997-11-26

    Samples were obtained for microbiological analysis from a granular activated carbon fluidized bed bioreactor (GAC-FBR). This GAC-FBR was in operation at a former manufactured gas plant (MGP) Site in Augusta Georgia for in situ groundwater bioremediation of organics. The samples included contaminated site groundwater, GAC-FBR effluent, and biofilm coated granular activated carbon at 5, 9, and 13 feet within the GAC-FBR column. The objective of this analysis was to correlate contaminant removal with microbiological activity within the GAC-FBR.

  18. Phototransformation of wastewater-derived trace organic contaminants in open-water unit process treatment wetlands.

    PubMed

    Jasper, Justin T; Sedlak, David L

    2013-10-01

    Open-water cells in unit process treatment wetlands can be used to exploit sunlight photolysis to remove trace organic contaminants from municipal wastewater effluent. To assess the performance of these novel systems, a photochemical model was calibrated using measured photolysis rates for atenolol, carbamazepine, propranolol, and sulfamethoxazole in wetland water under representative conditions. Contaminant transformation by hydroxyl radical ((•)OH) and carbonate radical ((•)CO3(-)) were predicted from steady-state radical concentrations measured at pH values between 8 and 10. Direct photolysis rates and the effects of light screening by dissolved organic matter on photolysis rates were estimated using solar irradiance data, contaminant quantum yields, and light screening factors. The model was applied to predict the land area required for 90% removal of a suite of wastewater-derived organic contaminants by sunlight-induced reactions under a variety of conditions. Results suggest that during summer, open-water cells that receive a million gallons of water per day (i.e., about 4.4 × 10(-2) m(3) s(-1)) of nitrified wastewater effluent can achieve 90% removal of most compounds in an area of about 15 ha. Transformation rates were strongly affected by pH, with some compounds exhibiting faster transformation rates under the high pH conditions associated with photosynthetic algae at the sediment-water interface and other contaminants exhibiting faster transformation rates at the circumneutral pH values characteristic of algae-free cells. Lower dissolved organic carbon concentrations typically resulted in increased transformation rates.

  19. Increasing subterranean mobilization of organic contaminants and petroleum by aqueous thermal oxidation

    DOEpatents

    Leif, Roald N.; Knauss, Kevin G.; Newmark, Robin L.; Aines, Roger D.; Eaker, Craig

    2002-01-01

    In situ hydrous pyrolysis/partial oxidation of organics at the site of the organics constrained in an subsurface reservoir produces surfactants that can form an oil/water emulsion that is effectively removed from an underground formation. The removal of the oil/water emulsions is particularly useful in several applications, e.g., soil contaminant remediation and enhanced oil recovery operations. A portion of the constrained organics react in heated reservoir water with injected steam containing dissolved oxygen gas at ambient reservoir conditions to produce such surfactants.

  20. Correlation of coprostanol to organic contaminants in coastal and estuarine sediments of the U. S

    SciTech Connect

    Shigenaka, G.; Price, J.E. )

    1988-10-01

    Results from the National Status and Trends Program, a nationwide effort to evaluate U.S. coastal and estuarine environmental quality, are analyzed to provide information about regional sources of organic contaminants in the benthic environment. Spearman's rank correlation procedure is applied to measurements of coprostanol, a chemical tracer of sewage, and three classes of organic compounds in sediments including selected major and trace elements, chlorinated pesticides, polychlorinated biphenyls (PCB), and polynuclear aromatic hydrocarbons (PAH). The results suggest that discharges from publicly owned treatment works are responsible for concentrations of the organic compounds encountered in the northeastern coastal region, while other sources may predominate in the other regions of the country.

  1. New biodegradable organic-soluble chelating agents for simultaneous removal of heavy metals and organic pollutants from contaminated media.

    PubMed

    Ullmann, Amos; Brauner, Neima; Vazana, Shlomi; Katz, Zhanna; Goikhman, Roman; Seemann, Boaz; Marom, Hanit; Gozin, Michael

    2013-09-15

    Advanced biodegradable and non-toxic organic chelators, which are soluble in organic media, were synthesized on the basis of the S,S-ethylenediamine-disuccinate (S,S-EDDS) ligand. The modifications suggested in this work include attachment of a lipophilic hydrocarbon chain ("tail") to one or both nitrogen atoms of the S,S-EDDS. The new ligands were designed and evaluated for application in the Sediments Remediation Phase Transition Extraction (SR-PTE) process. This novel process is being developed for the simultaneous removal of both heavy metals and organic pollutants from contaminated soils, sediments or sludge. The new chelators were designed to bind various target metal ions, to promote extraction of these ions into organic solvents. Several variations of attached tails were synthesized and tested. The results for one of them, N,N'-bis-dodecyl-S,S-EDDS (C24-EDDS), showed that the metal-ligand complexes are concentrated in the organic-rich phase in the Phase Transition Extraction process (more than 80%). Preliminary applications of the SR-PTE process with the C24-EDDS ligand were conducted also on actually contaminated sludge (field samples). The extraction of five toxic metals, namely, Cd, Cu, Ni, Pb and Zn was examined. In general, the extraction performance of the new ligand was not less than that of S,S-EDDS when a sufficient ligand-to-extracted ion ratio (about 4:1 was applied.

  2. First comprehensive screening of lipophilic organic contaminants in surface waters of the megacity Jakarta, Indonesia.

    PubMed

    Dsikowitzky, L; Sträter, M; Dwiyitno; Ariyani, F; Irianto, H E; Schwarzbauer, J

    2016-09-30

    Jakarta is an Indonesian coastal megacity with over 10 million inhabitants. The rivers flowing through the city receive enormous amounts of untreated wastewaters and discharge their pollutant loads into Jakarta Bay. We utilized a screening approach to identify those site-specific compounds that represent the major contamination of the cities' water resources, and detected a total number of 71 organic contaminants in Jakarta river water samples. Especially contaminants originating from municipal wastewater discharges were detected in high concentrations, including flame retardants, personal care products and pharmaceutical drugs. A flame retardant, a synthetic fragrance and caffeine were used as marker compounds to trace the riverine transport of municipal wastewaters into Jakarta Bay. These markers are also appropriate to trace municipal wastewater discharges to other tropical coastal ecosystems. This application is in particular useful to evaluate wastewater inputs from land-based sources to habitats which are sensitive to changing water quality, like coral reefs.

  3. Ultrasonic process for remediation of organics-contaminated groundwater/wastewater

    SciTech Connect

    Wu, J.M.; Peters, R.W.

    1995-07-01

    A technology is being developed that employs ultrasonic-wave energy for remediation of groundwater/wastewater contaminated with volatile organic compounds such as carbon tetrachloride (CCl{sub 4}) and trichloroethylene (TCE). This paper presents the updated results of a laboratory investigation of ultrasonic groundwater remediation using synthetic groundwaters prepared with laboratory deionized water. Key process parameters investigated included steady-state temperature, contaminant concentration, solution pH, sonication time, and intensity of the applied ultrasonics-wave energy. High destruction efficiencies of the target contaminants were achieved, and the sonication time required for a given degree of destruction decreased with increasing intensity of the applied ultrasonic energy. The sonication time can be further reduced by adding a chemical oxidant such as hydrogen peroxide.

  4. Phytoremediation of uranium-contaminated soils: Role of organic acids in triggering uranium hyperaccumulation in plants

    SciTech Connect

    Huang, J.W.; Blaylock, M.J.; Kapulnik, Y.; Ensley, B.D.

    1998-07-01

    Uranium phytoextraction, the use of plants to extract U from contaminated soils, is an emerging technology. The authors report on the development of this technology for the cleanup of U-contaminated soils. In this research, they investigated the effects of various soil amendments on U desorption from soil to soil solution, studied the physiological characteristics of U uptake and accumulation in plants, and developed techniques to trigger U hyperaccumulation in plants. A key to the success of U phytoextraction is to increase soil U availability to plants. The authors have found that some organic acids can be added to soils to increase U desorption from soil to soil solution and to trigger a rapid U accumulation in plants. Of the organic acids (acetic acid, citric acid, and malic acid) tested, citric acid was the most effective in enhancing U accumulation in plants. Shoot U concentrations of Brassica juncea and Brassica chinensis grown in a U-contaminated soil increased from less than 5 mg kg{sup {minus}1} to more than 5,000 mg kg{sup {minus}1} in citric acid-treated soils. To their knowledge, this is the highest shoot U concentration reported for plants grown on U-contaminated soils. Using this U hyperaccumulation technique, they are now able to increase U accumulation in shoots of selected plant species grown in two U-contaminated soils by more than 1,000-fold within a few days. The results suggest that U phytoextraction may provide an environmentally friendly alternative for the cleanup of U-contaminated soils.

  5. No enhancement in bioconcentration of organic contaminants by low levels of DOM

    USGS Publications Warehouse

    Haitzer, M.; Akkanen, J.; Steinberg, C.; Kukkonen, J.V.K.

    2001-01-01

    The aim of the present work was to systematically study the effect of low concentrations of dissolved organic matter (DOM) on the bioconcentration of organic contaminants, in order to show whether the phenomenon of enhanced bioconcentration factors (BCFs), that has been reported in the literature, is generally found at low levels of DOM or if BCF enhancements are more likely due to a random scatter in the experimental data. The first part of the study tested the hypothesis that low levels of DOM affect the uptake kinetics of organic contaminants, leading to transient enhancements of BCFs, relative to DOM-free controls, which could have been reported as BCF enhancements in short-term studies. We found that the presence of low concentrations of two different types of DOM consistently decreased the bioconcentration of benzo[a]pyrene (BaP) in the water flea Daphnia magna at all exposure times (1-24 h), and that no transient BCF enhancements occurred. The second part of the study systematically investigated if low concentrations of DOM from a wide range of different aquatic systems can cause enhancements in the bioconcentration of organic contaminants. Water fleas were exposed to combinations of four different organic contaminants (BaP, tetrachlorobiphenyl, pentachlorophenol and naphthalene) with low concentrations of 12 different types of DOM that had been collected from various regions throughout Europe. In several of the DOM treatments, we found mean BCFs being higher than mean BCFs in the controls (especially for naphthalene). This shows that the experimental setup used in this study (and similarly in previous studies) can produce seeming BCF enhancements at low concentrations of DOM. However, statistical analyses showed that treatment means were not significantly different from control means. Thus, this systematic study suggests that the BCF enhancements that have been reported in the literature are more likely the result of random, experimental variations than the

  6. Treatment adherence in psychoses.

    PubMed

    David, Anthony S

    2010-12-01

    A well-conducted randomised controlled trial of an intervention to improve treatment adherence in psychosis published in this issue shows beneficial effects on self- and observer-rated adherence and trends towards fewer hospital readmissions. Partial adherence is the single most important barrier to optimal treatment. National Institute for Health and Clinical Excellence guidelines on adherence need to be revised.

  7. Monitoring of organic contaminants in sediments using low field proton nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Zhang, Chi; Rupert, Yuri

    2016-04-01

    The effective monitoring of soils and groundwater contaminated with organic compounds is an important goal of many environmental restoration efforts. Recent geophysical methods such as electrical resistivity, complex conductivity, and ground penetrating radar have been successfully applied to characterize organic contaminants in the subsurface and to monitor remediation process both in laboratory and in field. Low field proton nuclear magnetic resonance (NMR) is a geophysical tool sensitive to the molecular-scale physical and chemical environment of hydrogen-bearing fluids in geological materials and shows promise as a novel method for monitoring contaminant remediation. This laboratory research focuses on measurements on synthetic samples to determine the sensitivity of NMR to the presence of organic contaminants and improve understanding of relationships between NMR observables, hydrological properties of the sediments, and amount and state of contaminants in porous media. Toluene, a light non-aqueous phase liquid (LNAPL) has been selected as a representative organic contaminant. Three types of porous media (pure silica sands, montmorillonite clay, and various sand-clay mixtures with different sand/clay ratios) were prepared as synthetic sediments. NMR relaxation time (T2) and diffusion-relaxation (D ‑ T2) correlation measurements were performed in each sediment saturated with water and toluene mixed fluid at assorted concentrations (0% toluene and 100% water, 1% toluene and 99% water, 5% toluene and 95% water, 25% toluene and 75% water, and 100% toluene and 0% water) to 1) understand the effect of different porous media on the NMR responses in each fluid mixture, 2) investigate the role of clay content on T2 relaxation of each fluid, 3) quantify the amount hydrocarbons in the presence of water in each sediment, and 4) resolve hydrocarbons from water in D ‑ T2 map. Relationships between the compositions of porous media, hydrocarbon concentration, and

  8. Monitoring of organic contaminants in sediments using low field proton nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Zhang, Chi; Rupert, Yuri

    2016-04-01

    The effective monitoring of soils and groundwater contaminated with organic compounds is an important goal of many environmental restoration efforts. Recent geophysical methods such as electrical resistivity, complex conductivity, and ground penetrating radar have been successfully applied to characterize organic contaminants in the subsurface and to monitor remediation process both in laboratory and in field. Low field proton nuclear magnetic resonance (NMR) is a geophysical tool sensitive to the molecular-scale physical and chemical environment of hydrogen-bearing fluids in geological materials and shows promise as a novel method for monitoring contaminant remediation. This laboratory research focuses on measurements on synthetic samples to determine the sensitivity of NMR to the presence of organic contaminants and improve understanding of relationships between NMR observables, hydrological properties of the sediments, and amount and state of contaminants in porous media. Toluene, a light non-aqueous phase liquid (LNAPL) has been selected as a representative organic contaminant. Three types of porous media (pure silica sands, montmorillonite clay, and various sand-clay mixtures with different sand/clay ratios) were prepared as synthetic sediments. NMR relaxation time (T2) and diffusion-relaxation (D - T2) correlation measurements were performed in each sediment saturated with water and toluene mixed fluid at assorted concentrations (0% toluene and 100% water, 1% toluene and 99% water, 5% toluene and 95% water, 25% toluene and 75% water, and 100% toluene and 0% water) to 1) understand the effect of different porous media on the NMR responses in each fluid mixture, 2) investigate the role of clay content on T2 relaxation of each fluid, 3) quantify the amount hydrocarbons in the presence of water in each sediment, and 4) resolve hydrocarbons from water in D - T2 map. Relationships between the compositions of porous media, hydrocarbon concentration, and hydraulic

  9. Assessing the fate of biodegradable volatile organic contaminants in unsaturated soil filter systems

    NASA Astrophysics Data System (ADS)

    Thullner, Martin; de Biase, Cecilia; Hanzel, Joanna; Reger, Daniel; Wick, Lukas; Oswald, Sascha; van Afferden, Manfred; Schmidt, Axel; Reiche, Nils; Jechalke, Sven

    2010-05-01

    The assessment of contaminant biodegradation in the subsurface is challenged by various abiotic processes leading to a reduction of contaminant concentration without a destructive mass removal of the contaminant. In unsaturated porous media, this interplay of processes is further complicated by volatilization. Many organic contaminants are sufficiently volatile to allow for significant fluxes from the water phase into the soil air, which can eventually lead to an emission of contaminants into the atmosphere. Knowledge of the magnitude of these emissions is thus required to evaluate the efficiency of bioremediation in such porous media and to estimate potential risks due to these emissions. In the present study, vertical flow constructed wetlands were investigated at the pilot scale as part of the SAFIRA II project. The investigated wetland system is intermittently irrigated by contaminated groundwater containing the volatile compounds benzene and MTBE. Measured concentration at the in- and outflow of the system demonstrate a high mass removal rate, but the highly transient flow and transport processes in the system challenge the quantification of biodegradation and volatilization and their contribution to the observed mass removal. By a combination of conservative solute tracer tests, stable isotope fractionation and measurements of natural radon concentration is the treated groundwater is was possible to determine the contribution of biodegradation and volatilization to total mass removal. The results suggest that for the investigated volatile compounds biodegradation is the dominating mass removal process with volatilization contributing only to minor or negligible amounts. These results can be confirmed by reactive transport simulations and were further supported by laboratory studies showing that also gas phase gradients of volatile compounds can be affected by biodegradation suggesting the unsaturated zone to act as a biofilter for contaminants in the soil air.

  10. Possibilities of implementation of bioavailability methods for organic contaminants in the Dutch Soil Quality Assessment Framework.

    PubMed

    Brand, Ellen; Lijzen, Johannes; Peijnenburg, Willie; Swartjes, Frank

    2013-10-15

    In the Netherlands, risk assessment of contaminated soils is based on determining the total contaminant concentration. If this measured soil concentration exceeds the Soil Quality Standards (SQS) a higher tier risk evaluation must be performed. Experiences from the field have given rise to the perception that performing risk evaluations based on (measured) total concentrations may lead to an inaccurate assessment of the actual risks. Assuming that only the bioavailable fraction is capable of exerting adverse effects in the soil ecosystem, it is suggested, that by taking bioavailability into account in a (higher tier) risk evaluation, a more effect-based risk assessment can be performed. Bioavailability has been a subject of research for several decades. However up to now bioavailability has not been implemented in the Dutch Soil Quality Assessment Framework. First actions were taken in the Netherlands to determine whether the concept of bioavailability could be implemented in the risk assessment of contaminated soils and to find out how bioavailability can become part of the Dutch Soil Quality Assessment Framework. These actions have led to a concrete proposal for implementation of bioavailability methods in the risk assessment of organic contaminants in soils. This paper focuses on the chemical prediction of bioavailability for ecological risk assessment of contaminated soils.

  11. Adherence to a healthy diet according to the World Health Organization guidelines and all-cause mortality in elderly adults from Europe and the United States.

    PubMed

    Jankovic, Nicole; Geelen, Anouk; Streppel, Martinette T; de Groot, Lisette C P G M; Orfanos, Philippos; van den Hooven, Edith H; Pikhart, Hynek; Boffetta, Paolo; Trichopoulou, Antonia; Bobak, Martin; Bueno-de-Mesquita, H B; Kee, Frank; Franco, Oscar H; Park, Yikyung; Hallmans, Göran; Tjønneland, Anne; May, Anne M; Pajak, Andrzej; Malyutina, Sofia; Kubinova, Růžena; Amiano, Pilar; Kampman, Ellen; Feskens, Edith J

    2014-11-15

    The World Health Organization (WHO) has formulated guidelines for a healthy diet to prevent chronic diseases and postpone death worldwide. Our objective was to investigate the association between the WHO guidelines, measured using the Healthy Diet Indicator (HDI), and all-cause mortality in elderly men and women from Europe and the United States. We analyzed data from 396,391 participants (42% women) in 11 prospective cohort studies who were 60 years of age or older at enrollment (in 1988-2005). HDI scores were based on 6 nutrients and 1 food group and ranged from 0 (least healthy diet) to 70 (healthiest diet). Adjusted cohort-specific hazard ratios were derived by using Cox proportional hazards regression and subsequently pooled using random-effects meta-analysis. During 4,497,957 person-years of follow-up, 84,978 deaths occurred. Median HDI scores ranged from 40 to 54 points across cohorts. For a 10-point increase in HDI score (representing adherence to an additional WHO guideline), the pooled adjusted hazard ratios were 0.90 (95% confidence interval (CI): 0.87, 0.93) for men and women combined, 0.89 (95% CI: 0.85, 0.92) for men, and 0.90 (95% CI: 0.85, 0.95) for women. These estimates translate to an increased life expectancy of 2 years at the age of 60 years. Greater adherence to the WHO guidelines is associated with greater longevity in elderly men and women in Europe and the United States.

  12. Field evidence for a protistan role in an organically-contaminated aquifer.

    PubMed

    Kinner, Nancy E; Harvey, Ronald W; Shay, David M; Metge, David W; Warren, Alan

    2002-10-15

    The association between protists, bacteria, and dissolved organic carbon (DOC) in an oxygen-depleted, 6 km-long wastewater contaminant plume within a sandy aquifer (Cape Cod, MA) was investigated by comparing abundance patterns along longitudinal and vertical transects and at a control site. Strong linear correlations were observed between unattached bacterial abundance and DOC for much of the upgradient-half of the plume (0.1-2.5 km downgradient from the source) that is characterized by quasi-steady state chemistry. However, a logarithmic decrease was observed between the number of protists supported per mg of DOC and the estimated age of the DOC within the plume. The relatively labile dissolved organic contaminants that characterize the groundwater sampled from the plume < or = 0.1 km downgradient from the contaminant source appeared to indirectly support 3-4 times as many protists (per mg of DOC) as the older, more recalcitrant DOC in the alkylbenzene sulfonate (ABS)-contaminated zone at 3 km downgradient (approximately 30 years travel time). Substantive numbers of protists (>10(4)/cm3) were recovered from suboxic zones of the plume. The higher than expected ratios of protists to unattached bacteria (10 to 100:1) observed in much of the plume suggest that protists may be grazing upon both surface-associated and unattached bacterial communities to meet their nutritional requirements. In closed bottle incubation experiments, the presence of protists caused an increase in bacterial growth rate, which became more apparent at higher amendments of labile DOC (3-20 mgC/L). The presence of protists resulted in an increase in the apparent substrate saturation level for the unattached bacterial community, suggesting an important role for protists in the fate of more-labile aquifer organic contaminants.

  13. A large-scale model for simulating the fate & transport of organic contaminants in river basins.

    PubMed

    Lindim, C; van Gils, J; Cousins, I T

    2016-02-01

    We present STREAM-EU (Spatially and Temporally Resolved Exposure Assessment Model for EUropean basins), a novel dynamic mass balance model for predicting the environmental fate of organic contaminants in river basins. STREAM-EU goes beyond the current state-of-the-science in that it can simulate spatially and temporally-resolved contaminant concentrations in all relevant environmental media (surface water, groundwater, snow, soil and sediments) at the river basin scale. The model can currently be applied to multiple organic contaminants in any river basin in Europe, but the model framework is adaptable to any river basin in any continent. We simulate the environmental fate of perfluoroctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in the Danube River basin and compare model predictions to recent monitoring data. The model predicts PFOS and PFOA concentrations that agree well with measured concentrations for large stretches of the river. Disagreements between the model predictions and measurements in some river sections are shown to be useful indicators of unknown contamination sources to the river basin.

  14. Evaluation of organic contamination in urban groundwater surrounding a municipal landfill, Zhoukou, China.

    PubMed

    Han, D M; Tong, X X; Jin, M G; Hepburn, Emily; Tong, C S; Song, X F

    2013-04-01

    This paper investigates the organic pollution status of shallow aquifer sediments and groundwater around Zhoukou landfill. Chlorinated aliphatic hydrocarbons, monocylic aromatic hydrocarbons, halogenated aromatic hydrocarbons, organochlorine pesticides and other pesticides, and polycyclic aromatic hydrocarbons (PAHs) have been detected in some water samples. Among the detected eleven PAHs, phenanthrene, fluorine, and fluoranthene are the three dominant in most of the groundwater samples. Analysis of groundwater samples around the landfill revealed concentrations of PAHs ranging from not detected to 2.19 μg/L. The results show that sediments below the waste dump were low in pollution, and the shallow aquifer, at a depth of 18-30 m, was heavily contaminated, particularly during the wet season. An oval-shaped pollution halo has formed, spanning 3 km from west to east and 2 km from south to north, and mainly occurs in groundwater depths of 2-4 m. For PAH source identification, both diagnostic ratios of selected PAHs and principal component analysis were studied, suggesting mixed sources of pyro- and petrogenic derived PAHs in the Zhoukou landfill. Groundwater table fluctuations play an important role in the distribution of organic pollutants within the shallow aquifer. A conceptual model of leachate migration in the Quaternary aquifers surrounding the Zhoukou landfill has been developed to describe the contamination processes based on the major contaminant (PAHs). The groundwater zone contaminated by leachate has been identified surrounding the landfill.

  15. Annual loads of organic contaminants in Chesapeake Bay contributed through fluvial transport

    SciTech Connect

    Foster, G.D.; Lippa, K.A.

    1994-12-31

    Organic contaminants in fluvial transport, atmospheric deposition, urban runoff, and shoreline erosion are being quantified and compared in an effort to understand contaminant inputs and mass balances in Chesapeake Bay. Concentrations of nine organonitrogen and organophosphorus (organo-N/P) pesticides, eight organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and four polynuclear aromatic hydrocarbons in fluvial transport were determined at the Susquehanna, Potomac, and James River fall lines for the period of March 1992 through February 1993. Together these rivers account for ca. 75% of the freshwater inflow to the bay from fluvial sources. Sampling was conducted monthly during base flow conditions and during all major storm events. Analysis of nanogram and picogram per liter concentrations of the organic contaminants was performed for both the dissolved and particulate phases of the surface water samples. Daily fluvial loads were calculated using an iterative-increment method from concentration and discharge data, and the resulting daily load estimates were summed to provide annual loads. Loads contributed by the three tributaries from March 1992 through February 1993 were 6.9 metric tons for the organo-N/P pesticides, 0.73 metric tons for the OC compounds and PCBs, and 1.2 metric tons for the PAH. Preliminary comparisons show that loads from fluvial transport are generally greater than other sources for most contaminants except PAH, where atmospheric deposition and urban runoff contribute greater loads of some compounds.

  16. Inverse modeling of the biodegradation of emerging organic contaminants in the soil-plant system.

    PubMed

    Hurtado, Carlos; Trapp, Stefan; Bayona, Josep M

    2016-08-01

    Understanding the processes involved in the uptake and accumulation of organic contaminants into plants is very important to assess the possible human risk associated with. Biodegradation of emerging contaminants in plants has been observed, but kinetical studies are rare. In this study, we analyse experimental data on the uptake of emerging organic contaminants into lettuce derived in a greenhouse experiment. Measured soil, root and leaf concentrations from four contaminants were selected within the applicability domain of a steady-state two-compartment standard plant uptake model: bisphenol A (BPA), carbamazepine (CBZ), triclosan (TCS) and caffeine (CAF). The model overestimated concentrations in most cases, when no degradation rates in plants were entered. Subsequently, biodegradation rates were fitted so that the measured concentrations were met. Obtained degradation kinetics are in the order, BPA < CAF ≈ TCS < CBZ in roots, and BPA ≈ TCS < CBZ < CAF in leaves. Kinetics determined by inverse modeling are, despite the inherent uncertainty, indicative of the dissipation rates. The advantage of the procedure that is additional knowledge can be gained from existing experimental data. Dissipation kinetics found via inverse modeling is not a conclusive proof for biodegradation and confirmation by experimental studies is needed. PMID:27179241

  17. Depositional history of organic contaminants in Narragansett Bay, Rhode Island, USA.

    PubMed

    Hartmann, Paul C; Quinn, James G; Cairns, Robert W; King, John W

    2005-04-01

    Sediment cores were taken at three locations in Narragansett Bay, Rhode Island, USA in 1997 and analyzed for a variety of organic contaminants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlordanes, linear alkyl benzenes (LABs), benzotriazoles (BZTs) and dichlorodiphenyltrichloroethanes (DDTs) and metabolites. The distributions of these chemicals at Apponaug Cove and in the Seekonk River indicate that there was a disturbance in the depositional environment relative to cores collected at these locations in 1986 demonstrating the potential for buried contaminants to be remobilized in the environment even after a period of burial. Sharp breaks in the concentration of several organic markers with known dates of introduction were successfully used to determine the sedimentation rate at Quonset Point. Both the Quonset Point and Seekonk River cores had subsurface maximums for DDTs, PCBs, PAHs and BZTs, which are consistent with expected inputs to the environment. The Apponaug Cove core showed an increase of most contaminants at the surface indicating a recent event in which more contaminated sediments were deposited at that location.

  18. Estrogenic contamination by manure fertilizer in organic farming: a case study with the lizard Podarcis sicula.

    PubMed

    Verderame, Mariailaria; Limatola, Ermelinda; Scudiero, Rosaria

    2016-01-01

    In the last years, worldwide organic farming has grown exponentially; as a consequence, the use of animal manure as a soil fertility source has become the principal agricultural choice. However, the use of manure as fertilizer can increase the amount of steroid hormone metabolites in the soil. In southern Italy, lacertidae lizards are the most abundant vertebrate group in agroecosystems and have been identified as potential model species for ecotoxicological studies. The aim of this study was to understand if the manure applied in organic farming has estrogen-like effects in the lizard Podarcis sicula. Adult male lizards were captured in two organic agricultural fields (manure-treated sites) and in an uncultivated field (control site). Lizards from the two organic farms displayed hepatic biosynthetic alterations typical of an estrogenic contamination; hepatocytes contained both vitellogenin and estrogen receptor alpha transcripts and proteins, detected by in situ hybridization and immunocytochemistry. The same cells did not show cadmium, lead and metallothionein accumulation, indicative of the lack of inorganic contamination. These findings suggest that exogenous estrogens, arising from the use of manure, could affect the welfare of wild animals and animal breeding, leading to bioaccumulation of estrogens in food chain, with possible risk for human consumers. For this reason, organic farming should implement the use of sustainable practices such as crop rotation to preserve the soil biological activity, rather than organic manure as fertilizer.

  19. Estrogenic contamination by manure fertilizer in organic farming: a case study with the lizard Podarcis sicula.

    PubMed

    Verderame, Mariailaria; Limatola, Ermelinda; Scudiero, Rosaria

    2016-01-01

    In the last years, worldwide organic farming has grown exponentially; as a consequence, the use of animal manure as a soil fertility source has become the principal agricultural choice. However, the use of manure as fertilizer can increase the amount of steroid hormone metabolites in the soil. In southern Italy, lacertidae lizards are the most abundant vertebrate group in agroecosystems and have been identified as potential model species for ecotoxicological studies. The aim of this study was to understand if the manure applied in organic farming has estrogen-like effects in the lizard Podarcis sicula. Adult male lizards were captured in two organic agricultural fields (manure-treated sites) and in an uncultivated field (control site). Lizards from the two organic farms displayed hepatic biosynthetic alterations typical of an estrogenic contamination; hepatocytes contained both vitellogenin and estrogen receptor alpha transcripts and proteins, detected by in situ hybridization and immunocytochemistry. The same cells did not show cadmium, lead and metallothionein accumulation, indicative of the lack of inorganic contamination. These findings suggest that exogenous estrogens, arising from the use of manure, could affect the welfare of wild animals and animal breeding, leading to bioaccumulation of estrogens in food chain, with possible risk for human consumers. For this reason, organic farming should implement the use of sustainable practices such as crop rotation to preserve the soil biological activity, rather than organic manure as fertilizer. PMID:26475047

  20. Global warming and environmental contaminants in aquatic organisms: the need of the etho-toxicology approach.

    PubMed

    Manciocco, Arianna; Calamandrei, Gemma; Alleva, Enrico

    2014-04-01

    Environmental contaminants are associated with a wide spectrum of pathological effects. Temperature increase affects ambient distribution and toxicity of these chemicals in the water environment, representing a potentially emerging problem for aquatic species with short-, medium- and long-term repercussions on human health through the food chain. We assessed peer-reviewed literature, including primary studies, review articles and organizational reports available. We focused on studies concerning toxicity of environmental pollutants within a global warming scenario. Existing knowledge on the effects that the increase of water temperature in a contaminated situation has on physiological mechanisms of aquatic organisms is presented. Altogether we consider the potential consequences for the human beings due to fish and shellfish consumption. Finally, we propose an etho-toxicological approach to study the effects of toxicants in conditions of thermal increase, using aquatic organisms as experimental models under laboratory controlled conditions.

  1. A stable isotope dilution method for measuring bioavailability of organic contaminants

    PubMed Central

    Delgado-Moreno, Laura; Gan, Jay

    2014-01-01

    Methods for determining bioavailability of organic contaminants suffer various operational limitations. We explored the use of stable isotope labeled references in developing an isotope dilution method (IDM) to measure the exchangeable pool (E) of pyrene and bifenthrin as an approximation of their bioavailability in sediments. The exchange of deuterated bifenthrin or pyrene with its native counterpart was completed within 48 h. The derived E was 38–82% for pyrene and 28–59% for bifenthrin. Regression between E and the sum of rapid and slow desorption fractions obtained from sequential desorption showed a slope close to 1.0. The ability of IDM to predict bioavailability was further shown from a strong relationship (r2 > 0.93) between E and bioaccumulation into Chironomus tentans. Given the abundance of stable isotope labeled references and their relatively easy analysis, the IDM has the potential to become a readily adoptable tool for estimating organic contaminants bioaccessibility in various matrices. PMID:23434573

  2. Contamination of soils and groundwater with new organic micropollutants: A review

    NASA Astrophysics Data System (ADS)

    Vodyanitskii, Yu. N.; Yakovlev, A. S.

    2016-05-01

    The input of organic micro- and nanopollutants to the environment has grown in recent years. This vast class of substances is referred to as emerging micropollutants, and includes organic chemicals of industrial, agricultural, and municipal provenance. There are three main sources of emerging pollutants coming to the environment, i.e., (1) upon soil fertilization with sewage and sewage sludge; (2) soil irrigation with reclaimed wastewater and (3) due to filtration from municipal landfills of solid wastes. These pollutants contaminate soil, affect its inhabitants; they are also consumed by plants and penetrate to the groundwater. The pharmaceuticals most strongly affect the biota (microorganisms, earthworms, etc.). The response of microorganisms in the contaminated soil is controlled not only by the composition and the number of emerging pollutants but also by the geochemical environment.

  3. Preliminary evaluation of selected in situ remediation technologies for Volatile Organic Compound contamination at Arid sites

    SciTech Connect

    Lenhard, R.J.; Gerber, M.A.; Amonette, J.E.

    1992-10-01

    To support the Volatile Organic Compounds-Arid Site (VOC-Arid) Integrated Demonstration (ID) in its technical, logistical, institutional, and economical testing of emerging environmental management and restoration technologies. Pacific Northwest Laboratory(a) is evaluating several in situ remediation technologies for possible inclusion in the demonstration. The evaluations are made with respect to the initial focus of the VOC-Arid ID: the carbon tetrachloride contamination at the Hanford Site, where it was disposed to the vadose zone along with other volatile and nonvolatile organic wastes. heavy metals, acids. and radionuclides. The purposes of this report are (1) to identify candidate in situ technologies for inclusion in the program, (2) to evaluate the candidate technologies based on their potential applicability to VOC contamination at arid sites and geologic conditions representative of the ID host site (i.e., Hanford Site), and (3) to prioritize those technologies for future US Department of Energy (DOE) support.

  4. Dying for a Tan: A Survey to Assess Solarium Adherence to World Health Organization Guidelines in Australia, New Zealand, and the United Kingdom

    PubMed Central

    Chandrasena, Amali; Amin, Kavit; Powell, Barry

    2013-01-01

    Background: Increased use of solariums worldwide has led to health concerns linking regular exposure to ultraviolet light with skin cancer. Most studies have attempted to delineate attitudes and motivations of users, with little inquiry into those entrusted as “service providers.” Methods: A questionnaire was designed specifically for the survey on the basis of World Health Organization guidelines. Twenty-one solariums in major cities from each country were randomly chosen via telephone directory and visited in Australia, New Zealand, and the United Kingdom. A prospective customer asked a series of questions to assess conformity with these guidelines. Results: Solariums in Australia were most successful at adhering to World Health Organization guidelines, followed closely by those in the United Kingdom. Overall, solariums in New Zealand did not comply as well, especially with the use of consent forms, and did not adequately inform customers of the potential adverse side effects including skin cancer risks. Conclusions: Our data have shown several differences in the way solariums conform to guidelines in our 3 chosen countries. A plausible reason for these differences is the difference in solarium regulations worldwide. The limited number of solariums selected for the survey, together with individual country variation, does not enable firm conclusions to be drawn about the operations of solariums in each country. However, it does provide knowledge of the variation between solariums and further suggests the need to evaluate the workings of these service providers in each country. PMID:24498456

  5. Importance of organic amendment characteristics on bioremediation of PAH-contaminated soil.

    PubMed

    Lukić, B; Huguenot, D; Panico, A; Fabbricino, M; van Hullebusch, E D; Esposito, G

    2016-08-01

    This study investigates the importance of the organic matter characteristics of several organic amendments (i.e., buffalo manure, food and kitchen waste, fruit and vegetables waste, and activated sewage sludge) and their influence in the bioremediation of a polycyclic aromatic hydrocarbons (PAH)-contaminated soil. The removal of low molecular weights (LMW) and high molecular weights (HMW) PAHs was monitored in four bioremediation reactors and used as an indicator of the role of organic amendments in contaminant removal. The total initial concentration of LMW PAHs was 234 mg kg(-1) soil (dry weight), while the amount for HMW PAHs was 422 mg kg(-1) soil (dry weight). Monitoring of operational parameters and chemical analysis was performed during 20 weeks. The concentrations of LMW PAH residues in soil were significantly lower in reactors that displayed a mesophilic phase, i.e., 11 and 15 %, compared to reactors that displayed a thermophilic phase, i.e., 29 and 31 %. Residual HMW PAHs were up to five times higher compared to residual LMW PAHs, depending on the reactor. This demonstrated that the amount of added organic matter and macronutrients such as nitrogen and phosphorus, the biochemical organic compound classes (mostly soluble fraction and proteins), and the operational temperature are important factors affecting the overall efficiency of bioremediation. On that basis, this study shows that characterization of biochemical families could contribute to a better understanding of the effects of organic amendments and clarify their different efficiency during a bioremediation process of PAH-contaminated soil.

  6. Importance of organic amendment characteristics on bioremediation of PAH-contaminated soil.

    PubMed

    Lukić, B; Huguenot, D; Panico, A; Fabbricino, M; van Hullebusch, E D; Esposito, G

    2016-08-01

    This study investigates the importance of the organic matter characteristics of several organic amendments (i.e., buffalo manure, food and kitchen waste, fruit and vegetables waste, and activated sewage sludge) and their influence in the bioremediation of a polycyclic aromatic hydrocarbons (PAH)-contaminated soil. The removal of low molecular weights (LMW) and high molecular weights (HMW) PAHs was monitored in four bioremediation reactors and used as an indicator of the role of organic amendments in contaminant removal. The total initial concentration of LMW PAHs was 234 mg kg(-1) soil (dry weight), while the amount for HMW PAHs was 422 mg kg(-1) soil (dry weight). Monitoring of operational parameters and chemical analysis was performed during 20 weeks. The concentrations of LMW PAH residues in soil were significantly lower in reactors that displayed a mesophilic phase, i.e., 11 and 15 %, compared to reactors that displayed a thermophilic phase, i.e., 29 and 31 %. Residual HMW PAHs were up to five times higher compared to residual LMW PAHs, depending on the reactor. This demonstrated that the amount of added organic matter and macronutrients such as nitrogen and phosphorus, the biochemical organic compound classes (mostly soluble fraction and proteins), and the operational temperature are important factors affecting the overall efficiency of bioremediation. On that basis, this study shows that characterization of biochemical families could contribute to a better understanding of the effects of organic amendments and clarify their different efficiency during a bioremediation process of PAH-contaminated soil. PMID:27083907

  7. Risks posed by trace organic contaminants in coastal sediments in the Pearl River Delta, China.

    PubMed

    Fung, C N; Zheng, G J; Connell, D W; Zhang, X; Wong, H L; Giesy, J P; Fang, Z; Lam, P K S

    2005-10-01

    Local marine environments in China's Pearl River Delta (PRD), the most rapidly developing region in one of the world's fastest growing economies, have been experiencing significant environmental stress during the past decades. This investigation was conducted to determine the status and trends of persistence organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and dioxin-related compounds in marine sediments collected from sixteen coastal stations in the Pearl River Delta (PRD) in March 2003. Elevated concentrations of PAHs (94-4300 ng/g), PCBs (6.0-290 ng/g), PHCs (14-150 microg/g), and DDTs (1.4-600 ng/g) were detected in sediment samples. In addition, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-like activities in the sediment samples were estimated to range from 0.3 to 440 pg TCDD-EQ/g. Sediments collected from Xiashan contained the greatest concentrations of trace organic contaminations amongst all the sampling stations in the present study. The degree of trace organic contamination was, in general, more severe at stations situated along the west shores of the PRD than their counterparts in the east. A preliminary assessment was performed to examine the probable risks to the marine ecosystem due to POPs. The results showed that OC pesticide contamination in the PRD was particularly serious and might pose a threat to the health of the marine inhabitants. PMID:16199239

  8. Sequester of metals and mineralization of organic contaminants with microbial mats

    SciTech Connect

    Bender, J.; Phillips, P.; Gould, J.P.

    1995-12-31

    Several recalcitrant organic contaminants are completely mineralized to simple products by microbial mats. Contaminants include chlordane, PCB, TNT, petroleum distillates, BM compounds and TCE in a mixed contaminant solution containing Zn. Degradation rates are relatively rapid under both dark and light conditions. In addition to complete degradation of organic materials, mats have been used to reduce selenate to elemental selenium, remove Pb, Cd, Cu, Zn, Co, Cr, Fe and Mn from water and sequester uranium (U{sup 238}) at a rate of 3.19 mg/m{sup 2}/h. Results of three pilot projects, including field pond treatment of mine drainage and bioreactor treatment of BTEX compounds will be reported. Microbial mats are natural heterotrophic and autotrophic communities dominated by cyanobacteria (blue-green algae). They are self-organized laminated structures annealed fightly together by slimy secretions from various microbial components. The surface slime of the mats effectively immobilizes the ecosystem to a variety of substrates, thereby stabilizing the most efficient internal microbial structure. Cyanobacteria mats are generated for bioremediation applications by enriching a water surface with ensiled grass clippings together with mat inocula developed in the laboratory.

  9. Comparison of contaminant and residue levels in organic and conventional milk and meat products from northern Italy.

    PubMed

    Ghidini, S; Zanardi, E; Battaglia, A; Varisco, G; Ferretti, E; Campanini, G; Chizzolini, R

    2005-01-01

    Due to the growing interest in organic products, a comparison between the chemical safety of organic and conventional products was undertaken. Milk and meat were the products chosen for study. The parameters evaluated to assess chemical safety were organochlorine pesticides, polychlorinated biphenyls (PCBs), lead, cadmium and mycotoxin contamination. Pesticides and PCBs residues in both organic and conventional milk and meat were lower than legal limits. Lead and cadmium residues were very low and did not differ between organic and conventional products. However, aflatoxin M1 contamination in some but not all samples of organic milk was significantly higher than those of conventional milk, although factors other than organic production might be implicated.

  10. Characterization of organic contaminants in environmental samples associated with mount St. Helens 1980 volcanic eruption

    USGS Publications Warehouse

    Pereira, W.E.

    1982-01-01

    Volcanic ash, surface-water, and bottom-material samples obtained in the vicinity of Mount St. Helens after the May 18, 1980, eruption were analyzed for organic contaminants by using capillary gas chromatography-mass spectrometry-computer techniques. Classes of compounds identified include n-alkanes, fatty acids, dicarboxylic acids, aromatic acids and aldehydes, phenols, resin acids, terpenes, and insect juvenile hormones. The most probable source of these compounds is from pyrolysis of plant and soil organic matter during and after the eruption. The toxicity of selected compounds and their environmental significance are discussed.

  11. Use of inorganic dryer-salts in the determination of organic contaminants in air

    SciTech Connect

    Simonov, V.A.

    1985-09-01

    This paper presents results of a study of the adsorptive activity of a number of inorganic salts relative to water vapor and to organic vapors in air under the dynamic conditions which are uses in the indicator tube method. Data are also given on the properties of dryer salts having a surface modified with glycerin. It is shown that lithium chloride on porcelain and potassium carbonate having a surface modified with glycerin can be used to dry air in determining contaminants of nonpolar and polar organic substances in it. Anhydrone on porcelain, calcium chloride, and potassium carbonate absorb some substances which are being determined and therefore are less suitable.

  12. Approaches for assessment of terrestrial vertebrate responses to contaminants: moving beyond individual organisms

    USGS Publications Warehouse

    Albers, P.H.; Heinz, G.H.; Hall, R.J.; Albers, Peter H.; Heinz, Gary H.; Ohlendorf, Harry M.

    2000-01-01

    Conclusions: A need for a broader range ofinformation on effects of contaminants on individuals exists among the 4 classes of terrestrial vertebrates, especially mammals, reptiles, and amphibians. Separation of contaminant effects from other effects and reduction of speculative extrapolation within and among species requires information that can be produced only by combined field and laboratory investigations that incorporate seasonal or annual cycles and important spatial and interaction conditions. Assessments of contaminant effects at the population level and higher are frequently dependent on extrapolations from a lower organizational level. Actual measurements of the effects of contaminants on populations or communities, possibly in conjunction with case studies that establish relations between effects on individuals and effects on populations, are needed to reduce the uncertainty associated with these extrapolations. Associated with these assessment levels is the need for acceptable definitions of what we mean when we refer to a 'meaningful population change' or an 'effect on communities or ecosystems.' At these higher levels of organization we are also confronted with the need for procedures useful for separating contaminant effects from effects caused by other environmental conditions. Although the bulk of literature surveyed was of the focused cause-and-effect type that is necessary for proving relations between contaminants and wildlife, community or ecosystem field assessments, as sometimes performed with reptiles and amphibians, might be a useful alternative for estimating the potential of a contaminant to cause environmental harm. Assumptions about the special usefulness of reptiles and amphibians as environmental indicators ought to be tested with comparisons to mammals and birds. Information on the effects of contaminants above the individual level is needed to generate accurate estimates of the potential consequences of anthropogenic pollution (e

  13. Estimates of atmospheric deposition of submicron particle-associated combustion derived organic contaminants to Chesapeake Bay

    SciTech Connect

    Leister, D.L. |; Baker, J.E.

    1994-12-31

    Once emitted into the atmosphere, combustion derived organic contaminants partition between gaseous and particle phases. In order to estimate the wet and dry removal of contaminants from the atmospheric to surface waters, it is necessary to measure gaseous and particle-associated contaminant concentrations because the deposition mechanisms of each phase differ. The authors estimate dry and wet depositional fluxes of polycyclic aromatic hydrocarbons (PAH) as a function of large and small particles to provide insight to the contribution of small particles to the overall atmospheric flux of organic contaminants to surface waters. Utilizing data gathered from concurrent measurements of 10 PAHs associated with particles in rain an in the atmosphere adjacent to Chesapeake Bay, and from PAH particle-size distribution data recently collected at Egbert, Ontario, calculated non-crustal PAH dry particle fluxes range from 40 to as high as 160 ng/m{sup 2}/month. Despite the lower estimated deposition velocity for noncrustal particles relative to that for partially crustal particles, non-crustal PAH particle fluxes are about a factor of five larger than those calculated for particles with a partial crustal component. Monthly wet fluxes of submicron particles range from 12 to 260 ng/m{sup 2}/month and in contrast to dry periods, are similar to those for large particles. Their calculations suggest that the atmospheric loading of submicron particle associated PAHs on an annual basis during dry and wet periods are significant due to the high concentrations of contaminants in this size range in both air and rain.

  14. Deposition and accumulation of airborne organic contaminants in Yosemite National Park, Calfornia

    USGS Publications Warehouse

    Mast, Alisa M.; Alvarez, David A.; Zaugg, Steven D.

    2012-01-01

    Deposition and accumulation of airborne organic contaminants in Yosemite National Park were examined by sampling atmospheric deposition, lichen, zooplankton, and lake sediment at different elevations. Passive samplers were deployed in high-elevation lakes to estimate surface-water concentrations. Detected compounds included current-use pesticides chlorpyrifos, dacthal, and endosulfans and legacy compounds chlordane, dichlorodiphenyltrichloroethane-related compounds, dieldrin, hexachlorobenzene, and polychlorinated biphenyls. Concentrations in snow were similar among sites and showed little variation with elevation. Endosulfan concentrations in summer rain appeared to coincide with application rates in the San Joaquin Valley. More than 70% of annual pesticide inputs from atmospheric deposition occurred during the winter, largely because most precipitation falls as snow. Endosulfan and chlordane concentrations in lichen increased with elevation, indicating that mountain cold-trapping might be an important control on accumulation of these compounds. By contrast, chlorpyrifos concentrations were inversely correlated with elevation, indicating that distance from source areas was the dominant control. Sediment concentrations were inversely correlated with elevation, possibly because of the organic carbon content of sediments but also perhaps the greater mobility of organic contaminants at lower elevations. Surface-water concentrations inferred from passive samplers were at sub-parts-per-trillion concentrations, indicating minimal exposure to aquatic organisms from the water column. Concentrations in sediment generally were low, except for dichlorodiphenyldichloroethane in Tenaya Lake, which exceeded sediment guidelines for protection of benthic organisms.

  15. Organic Contamination Baseline Study in NASA Johnson Space Center Astromaterials Curation Laboratories

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Allen, Carlton C.; Allton, Judith H.

    2014-01-01

    Future robotic and human spaceflight missions to the Moon, Mars, asteroids, and comets will require curating astromaterial samples with minimal inorganic and organic contamination to preserve the scientific integrity of each sample. 21st century sample return missions will focus on strict protocols for reducing organic contamination that have not been seen since the Apollo manned lunar landing program. To properly curate these materials, the Astromaterials Acquisition and Curation Office under the Astromaterial Research and Exploration Science Directorate at NASA Johnson Space Center houses and protects all extraterrestrial materials brought back to Earth that are controlled by the United States government. During fiscal year 2012, we conducted a year-long project to compile historical documentation and laboratory tests involving organic investigations at these facilities. In addition, we developed a plan to determine the current state of organic cleanliness in curation laboratories housing astromaterials. This was accomplished by focusing on current procedures and protocols for cleaning, sample handling, and storage. While the intention of this report is to give a comprehensive overview of the current state of organic cleanliness in JSC curation laboratories, it also provides a baseline for determining whether our cleaning procedures and sample handling protocols need to be adapted and/or augmented to meet the new requirements for future human spaceflight and robotic sample return missions.

  16. Deposition and accumulation of airborne organic contaminants in Yosemite National Park, California.

    PubMed

    Mast, M Alisa; Alvarez, David A; Zaugg, Steven D

    2012-03-01

    Deposition and accumulation of airborne organic contaminants in Yosemite National Park were examined by sampling atmospheric deposition, lichen, zooplankton, and lake sediment at different elevations. Passive samplers were deployed in high-elevation lakes to estimate surface-water concentrations. Detected compounds included current-use pesticides chlorpyrifos, dacthal, and endosulfans and legacy compounds chlordane, dichlorodiphenyltrichloroethane-related compounds, dieldrin, hexachlorobenzene, and polychlorinated biphenyls. Concentrations in snow were similar among sites and showed little variation with elevation. Endosulfan concentrations in summer rain appeared to coincide with application rates in the San Joaquin Valley. More than 70% of annual pesticide inputs from atmospheric deposition occurred during the winter, largely because most precipitation falls as snow. Endosulfan and chlordane concentrations in lichen increased with elevation, indicating that mountain cold-trapping might be an important control on accumulation of these compounds. By contrast, chlorpyrifos concentrations were inversely correlated with elevation, indicating that distance from source areas was the dominant control. Sediment concentrations were inversely correlated with elevation, possibly because of the organic carbon content of sediments but also perhaps the greater mobility of organic contaminants at lower elevations. Surface-water concentrations inferred from passive samplers were at sub-parts-per-trillion concentrations, indicating minimal exposure to aquatic organisms from the water column. Concentrations in sediment generally were low, except for dichlorodiphenyldichloroethane in Tenaya Lake, which exceeded sediment guidelines for protection of benthic organisms.

  17. Effects Of Evaporation Rate of Some Common Organic Contaminants on Hydraulic Conductivity of Aquifer Sand

    NASA Astrophysics Data System (ADS)

    Saud, Q. J.; Hasan, S. E.

    2014-12-01

    As part of a larger study to investigate potential effects of hydrocarbons on the geotechnical properties of aquifer solids, a series of laboratory experiments were carried out to ascertain the influence of evaporation rate of some common and widespread organic contaminants on the hydraulic conductivity of aquifer sand. Gasoline and its constituent chemicals-benzene, toluene, ethylbenzene, xylene (BTEX), isooctane- and trichloroethylene (TCE) were used to contaminate sand samples collected from the aquifer and vadose zone, at varying concentrations for extended periods of time. The goal was to study any change in the chemical makeup of the contaminants and its control on hydraulic conductivity of the sand. It was found that: (a) gasoline breaks down into constituent compounds when subjected to evaporation, e.g. during oil spills and leaks; and (b) lighter compounds volatilize faster and in the following order: TCE> benzene > isooctane > toluene > gasoline> ethylbenzene > xylene. In addition, these contaminants also caused a decrease in hydraulic conductivity of sand by up to 60% as compared to the uncontaminated sand. The inherent differences in the chemical structure of contaminating chemicals influenced hydraulic conductivity such that the observed decrease was greater for aliphatic than aromatic and chlorinated hydrocarbons. The presentation includes details of the experimental set up; evaporation rate, and geotechnical tests; X-ray diffraction and scanning electron microscope studies; and data analyses and interpretation. Rate of evaporation test indicates that residual LNAPLs will occupy a certain portion of the pores in the soil either as liquid or vapor phase in the vadose zone, and will create a coating on the adjacent solid mineral grains in the aquifer. Replacement of air by the LNAPLs along with grain coatings and the intramolecular forces would impede groundwater movement, thus affecting overall permeability of contaminated aquifers. Keywords: aquifer

  18. Incineration of contaminated organic solvents in a fluidized-bed calciner

    SciTech Connect

    Schindler, R.E.

    1980-01-01

    The reprocessing of expended reactor fuels at the Idaho Chemical Processing Plant (ICPP) generates contaminated organic solvents. An evaluation of potential management alternatives shows that several are suitable for management of contaminated solvents containing tri-butyl phosphate (TBP): the solvent could be burned in a commercially-available burner which absorbs the phosphorus on a fluidized-bed of limestone leaving a solid product for burial; the solvent could be burned in a small fluidized-bed calciner which solidifies non-radioactive feed by in-bed combustion of the contaminated solvent. The fluidized-bed absorbs the phosphate forming a solid product for burial; the solvents could be solidified with a gel or sorbant for burial if the reprocessing system were modified to reduce the solvent volume; and the contaminated solvent could be burned in an existing fluidized-bed calciner designed for solidifying high-level aqueous wastes. Burning the solvent in the existing calciner was selected for process verification because it provides an existing burner, off-gas system, and solids transfer and storage system. No additional wastes are generated. A set of four pilot-plant tests verified the absence of adverse effects from the phosphorus in the fuel when calcining simulated ICPP aqueous wastes. Essentially all of the phosphorus remained in the calcined solids with only a neglegible quantity remaining in the scrubbed off-gas. Combustion efficiency was high (93 to 96%). There were no observable adverse effects on solids in the scrubbing system, corrosion rates, or solids flowability (for retrieval). Conclusions of general applicability are: alternative technologies are available for disposal of contaminated solvents, and the use of an existing fuel-using facility, e.g., calciner or incinerator - designed for contaminated wastes will usually be cost effective.

  19. Measuring the release of organic contaminants from melting snow under controlled conditions.

    PubMed

    Meyer, Torsten; Lei, Ying Duan; Wania, Frank

    2006-05-15

    The release of organic contaminants from a melting snowpack may result in temporary concentration peaks in receiving water bodies and respective pulse exposure of aquatic organisms. It is thus of considerable interest to gain a mechanistic and quantitative understanding of the processes determining the dynamic behavior of organic chemicals during snowmelt. Uniformly structured and contaminated snow was produced with the help of a newly designed snow gun and exposed to predetermined temperature conditions in a temperature-controlled cold room. The dry density and liquid water content during four freeze-thaw cycles was recorded continuously at different layers within the snowpack using time domain reflectometry, providing information on meltwater production and propagation as well as snow metamorphism. Fractionated meltwater samples were filtered and the dissolved and particle phase analyzed for five polycyclic aromatic hydrocarbons (PAHs) using gas chromatography/ mass spectrometry. The distribution of the PAHs between the dissolved and particulate fractions of the meltwater was strongly related to their hydrophobicity. Particle-bound PAHs were released late during the snowmelt, whereas PAHs in the dissolved phase were released uniformly during a two day melting period. Even though conductivity measurements indicated a preferential early elution of ions in the first meltwater fractions, no such "first flush" behavior was observed for soluble PAH. The developed laboratory-based approach opens up for the first time the possibility of reproducible experiments on organic contaminant behavior in snow. Future experiments will explore, in detail, how the properties of organic chemicals, the physical and chemical properties of the snowpack, and the temperature variations before and during the time of melting interact to determine the timing of chemical release from a snowpack. PMID:16749700

  20. Assessing the toxicity of contaminated soils using the nematode Caenorhabditis elegans as test organism.

    PubMed

    Höss, S; Jänsch, S; Moser, T; Junker, T; Römbke, J

    2009-10-01

    In this study, nine uncontaminated reference soils and 22 contaminated soils with different physico-chemical properties and contamination patterns were tested with a standardized toxicity test, using the nematode, Caenorhabditis elegans, as test organism. Fertility, growth and reproduction of C. elegans in the soils were compared with the exposure in standard soil Lufa St.2.2. C. elegans showed 100% fertility and a very low variability of growth in the reference soils. Although, reproduction varied considerably between the various reference soils, validity criteria (>30 offspring per test organism) were met in all reference soils. Moreover, Lufa St. 2.2 turned out to be a suitable and representative control soil. In order to clearly classify the effects of the polluted soils on C. elegans, toxicity thresholds were derived for nematode fertility (20% inhibition), growth (10% inhibition) and reproduction (40% inhibition) on the basis of the test inherent variability (MDD=minimal detectable difference), as well as their variability between the uncontaminated reference soils (MTI=maximal tolerable inhibition). The contaminated soils showed clear toxic effects on the nematodes, whereas the toxicity was better correlated to organic than to heavy metal contamination in bulk soil. Interestingly, the results of the nematode toxicity test were not well correlated with those of tests with oligochaetes, collembolans and plants, performed with the same soils, showing that the results are not redundant. The toxicity test using C. elegans turned out to be suitable for testing the toxicity of field collected soils and might by a valuable addition to soil test batteries.

  1. Persistence and potential effects of complex organic contaminant mixtures in wastewater-impacted streams.

    PubMed

    Barber, Larry B; Keefe, Steffanie H; Brown, Greg K; Furlong, Edward T; Gray, James L; Kolpin, Dana W; Meyer, Michael T; Sandstrom, Mark W; Zaugg, Steven D

    2013-03-01

    Natural and synthetic organic contaminants in municipal wastewater treatment plant (WWTP) effluents can cause ecosystem impacts, raising concerns about their persistence in receiving streams. In this study, Lagrangian sampling, in which the same approximate parcel of water is tracked as it moves downstream, was conducted at Boulder Creek, Colorado and Fourmile Creek, Iowa to determine in-stream transport and attenuation of organic contaminants discharged from two secondary WWTPs. Similar stream reaches were evaluated, and samples were collected at multiple sites during summer and spring hydrologic conditions. Travel times to the most downstream (7.4 km) site in Boulder Creek were 6.2 h during the summer and 9.3 h during the spring, and to the Fourmile Creek 8.4 km downstream site times were 18 and 8.8 h, respectively. Discharge was measured at each site, and integrated composite samples were collected and analyzed for >200 organic contaminants including metal complexing agents, nonionic surfactant degradates, personal care products, pharmaceuticals, steroidal hormones, and pesticides. The highest concentration (>100 μg L(-1)) compounds detected in both WWTP effluents were ethylenediaminetetraacetic acid and 4-nonylphenolethoxycarboxylate oligomers, both of which persisted for at least 7 km downstream from the WWTPs. Concentrations of pharmaceuticals were lower (<1 μg L(-1)), and several compounds, including carbamazepine and sulfamethoxazole, were detected throughout the study reaches. After accounting for in-stream dilution, a complex mixture of contaminants showed little attenuation and was persistent in the receiving streams at concentrations with potential ecosystem implications. PMID:23398602

  2. Long-term effects of dredging operations program. Effects of sediment organic-matter composition on bioaccumulation of sediment organic contaminants: Interim results. Final report

    SciTech Connect

    Brannon, J.M.; Price, C.B.; Reilly, F.J.; Pennington, J.C.; McFarland, V.A.

    1991-06-01

    The relationship of sediment-bound polychlorinated biphenyl (PCB) 153 and fluoranthene to bioaccumulation by worms and clams and the relationship of sediment-bound PCB 153 and fluoranthene to concentrations in the interstitial water were examined. Bioaccumulation by both worms and clams was observed in all sediments. Apparent preference factor (APF) values showed that steady state was reached between sediment-bound contaminants and organism lipid pools. The APF values of organisms were close to the theoretical value for both contaminants in all sediments. These results showed that sediment total organic carbon (TOC) in conjunction with octanol water partition coefficients of nonpolar organic contaminants is a viable approach for predicting bioaccumulation of such compounds by infaunal organisms. Actual concentrations of contaminants in interstitial water were either overestimated or underestimated by the relationship between TOC and humic + fulvic acid organic matter fractions and sediment contaminant concentrations. Prediction of interstitial water concentrations was not as successful as use of APFs. The lack of agreement between predicted and actual interstitial water results was due to factors such as the presence of interstitial water contaminants bounds to microparticulates and dissolved organic material and the kind of organic material in the sediment.

  3. Indoor air condensate as a novel matrix for monitoring inhalable organic contaminants.

    PubMed

    Roll, Isaac B; Halden, Rolf U; Pycke, Benny F G

    2015-05-15

    With the population of developed nations spending nearly 90% of their time indoors, indoor air quality (IAQ) is a critical indicator of human health risks from inhalation of airborne contaminants. We present a novel approach for qualitative monitoring of IAQ through the collection and analysis of indoor air condensate discharged from heat exchangers of heating, ventilation, and air conditioning (HVAC) systems. Condensate samples were collected from six suburban homes and one business in Maricopa County, Arizona, concentrated via solid-phase extraction, analyzed for 10 endocrine disrupting chemicals (EDCs) by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and screened for additional organic compounds by gas chromatography-mass spectrometry (GC-MS). All 10 EDCs were detected in at least one of the sampled buildings. More than 100 additional compounds were detected by GC-MS, of which 40 were tentatively identified using spectral database searches. Twelve compounds listed as designated chemicals for biomonitoring by the California Environmental Contaminant Biomonitoring Program were detected. Microfiltration of condensate samples prior to extraction had no discernable effect on contaminant concentration, suggesting that contaminants were freely dissolved or associated with inhalable, submicron particles. This study is the first to document the utility of HVAC condensate for the qualitative assessment of indoor air for pollutants. PMID:25706557

  4. Indoor air condensate as a novel matrix for monitoring inhalable organic contaminants.

    PubMed

    Roll, Isaac B; Halden, Rolf U; Pycke, Benny F G

    2015-05-15

    With the population of developed nations spending nearly 90% of their time indoors, indoor air quality (IAQ) is a critical indicator of human health risks from inhalation of airborne contaminants. We present a novel approach for qualitative monitoring of IAQ through the collection and analysis of indoor air condensate discharged from heat exchangers of heating, ventilation, and air conditioning (HVAC) systems. Condensate samples were collected from six suburban homes and one business in Maricopa County, Arizona, concentrated via solid-phase extraction, analyzed for 10 endocrine disrupting chemicals (EDCs) by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and screened for additional organic compounds by gas chromatography-mass spectrometry (GC-MS). All 10 EDCs were detected in at least one of the sampled buildings. More than 100 additional compounds were detected by GC-MS, of which 40 were tentatively identified using spectral database searches. Twelve compounds listed as designated chemicals for biomonitoring by the California Environmental Contaminant Biomonitoring Program were detected. Microfiltration of condensate samples prior to extraction had no discernable effect on contaminant concentration, suggesting that contaminants were freely dissolved or associated with inhalable, submicron particles. This study is the first to document the utility of HVAC condensate for the qualitative assessment of indoor air for pollutants.

  5. Contamination of estuarine water, biota, and sediment by halogenated organic compounds: A field study

    USGS Publications Warehouse

    Pereira, W.E.; Rostad, C.E.; Chiou, C.T.; Brinton, T.I.; Barber, L.B.; Demcheck, D.K.; Demas, C.R.

    1988-01-01

    Studies conducted in the vicinity of an industrial outfall in the Calcasieu River estuary, Louisiana, have shown that water, bottom and suspended sediment, and four different species of biota are contaminated with halogenated organic compounds (HOC) including haloarenes. A "salting-out" effect in the estuary moderately enhanced the partitioning tendency of the contaminants into biota and sediments. Contaminant concentrations in water, suspended sediments, and biota were found to be far below the values predicted on the basis of the assumption of phase equilibria with respect to concentrations in bottom sediment. Relative concentration factors of HOC between biota (catfish) and bottom sediment increased with increasing octanol/estuarine water partition coefficients (Kow*), maximizing at log Kow* of about 5, although these ratios were considerably less than equilibrium values. In contrast, contaminant concentrations in water, biota, and suspended sediments were much closer to equilibrium values. Bioconcentration factors of HOC determined on the basis of lipid content for four different biotic species correlated reasonably well with equilibrium triolein/water partition coefficients (Ktw).

  6. Interactions of nano-oxides with low-molecular-weight organic acids in a contaminated soil.

    PubMed

    Vítková, Martina; Komárek, Michael; Tejnecký, Václav; Šillerová, Hana

    2015-08-15

    Various low-molecular-weight organic acids (LMWOAs) play an important role in the mobilisation of contaminants and their subsequent uptake by plants. Nano-maghemite (NM) and an amorphous Mn oxide (AMO) were investigated for their stabilisation potential under simulated rhizosphere conditions in terms of their use during chemical stabilisation and aided phytostabilisation of metal(loid)s in contaminated soils. In order to understand the reactivity of these potential sorbents of contaminants in soils and subsequent mobility of metal(loid)s, a set of time-dependent batch leaching experiments was performed using a mix of acetic, lactic, citric, malic and formic acids simulating root exudates. Despite being relatively unstable under given conditions, the AMO proved to be an efficient amendment for rapid stabilisation of both metals and As compared to NM. Generally, low pH (∼ 4) and the presence of citrate complexes resulted in higher mobility of metals in the non- and NM-amended soil. In contrast, the presence of AMO in the soil accelerated the neutralisation reactions related to pH increase and (co-) precipitation of secondary Fe/Mn/Al oxyhydroxides. Mineralogical transformations of the AMO showed to be crucial for contaminant immobilisation. PMID:25814334

  7. Uptake and depuration of nonionic organic contaminants from sediment by the oligochaete, Lumbriculus variegatus

    USGS Publications Warehouse

    Ingersoll, C.G.; Brunson, E.L.; Wang, F.N.; Dwyer, J.; Ankley, G.T.; Mount, D.R.; Huckins, J.; Petty, J.; Landrum, P.F.

    2003-01-01

    Uptake of sediment-associated contaminants by the oligochaete Lumbriculus variegatus was evaluated after 1, 3, 7, 14, 28, and 56 d of exposure to a field-collected sediment contaminated with DDT and its metabolites, dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE), or to a field-collected sediment contaminated with polycyclic aromatic hydrocarbons (PAHs). Depuration of contaminants by oligochaetes in a control sediment or in water was also evaluated over a 7-d period after 28 d of exposure to the field-collected sediments. Accumulation of PAHs with a log octanol-water partitioning coefficient (log Kow) 5.6 or DDD and DDE typically exhibited a steady increase from day 1 to about day 14 or 28, followed by a plateau. Therefore, exposures conducted for a minimum of 14 to 28 d better reflected steady-state concentrations for DDT and its metabolites and for PAHs. Depuration rates for DDT and its metabolites and high-Kow PAHs were much higher in organisms held in clean sediment relative to both water-only depuration and model predictions. This suggests that depuration in clean sediment may artificially accelerate depuration of hydrophobic compounds. Comparisons between laboratory-exposed L. variegatus and oligochaetes collected in the field from these sediments indicate that results of laboratory tests can be extrapolated to the field with a reasonable degree of certainty.

  8. Size-Selective Predation on Groundwater Bacteria by Nanoflagellates in an Organic-Contaminated Aquifer

    PubMed Central

    Kinner, N. E.; Harvey, R. W.; Blakeslee, K.; Novarino, G.; Meeker, L. D.

    1998-01-01

    Time series incubations were conducted to provide estimates for the size selectivities and rates of protistan grazing that may be occurring in a sandy, contaminated aquifer. The experiments involved four size classes of fluorescently labeled groundwater bacteria (FLB) and 2- to 3-μm-long nanoflagellates, primarily Spumella guttula (Ehrenberg) Kent, that were isolated from contaminated aquifer sediments (Cape Cod, Mass.). The greatest uptake and clearance rates (0.77 bacteria · flagellate−1 · h−1 and 1.4 nl · flagellate−1 · h−1, respectively) were observed for 0.8- to 1.5-μm-long FLB (0.21-μm3 average cell volume), which represent the fastest growing bacteria within the pore fluids of the contaminated aquifer sediments. The 19:1 to 67:1 volume ratios of nanoflagellate predators to preferred bacterial prey were in the lower end of the range commonly reported for other aquatic habitats. The grazing data suggest that the aquifer nanoflagellates can consume as much as 12 to 74% of the unattached bacterial community in 1 day and are likely to have a substantive effect upon bacterial degradation of organic groundwater contaminants. PMID:9464400

  9. Size-selective predation on groundwater bacteria by nanoflagellates in an organic-contaminated aquifer

    USGS Publications Warehouse

    Kinner, N.E.; Harvey, R.W.; Blakeslee, K.; Novarino, G.; Meeker, L.D.

    1998-01-01

    Time series incubations were conducted to provide estimates for the size selectivities and rates of protistan grazing that may be occurring in a sandy, contaminated aquifer. The experiments involved four size classes of fluorescently labeled groundwater bacteria (FLB) and 2- to 3-??m-long nanoflagellates, primarily Spumella guttula (Ehrenberg) Kent, that were isolated from contaminated aquifer sediments (Cape Cod, Mass.). The greatest uptake and clearance rates (0.77 bacteria flagellate-1 ?? h-1 and 1.4 nl. flagellate-1 ?? h-1, respectively) were observed for 0.8- to 1.5-??m- long FLB (0.21-??m3 average cell volume), which represent the fastest growing bacteria within the pore fluids of the contaminated aquifer sediments. The 19:1 to 67:1 volume ratios of nanoflagellate predators to preferred bacterial prey were in the lower end of the range commonly reported for other aquatic habitats. The grazing data suggest that the aquifer nanoflagellates can consume as much as 12 to 74% of the unattached bacterial community in 1 day and are likely to have a substantive effect upon bacterial degradation of organic groundwater contaminants.

  10. Effect of ozone exposure on the oxidation of trace organic contaminants in wastewater.

    PubMed

    Wert, Eric C; Rosario-Ortiz, Fernando L; Snyder, Shane A

    2009-03-01

    Three tertiary-treated wastewater effluents were evaluated to determine the impact of wastewater quality (i.e. effluent organic matter (EfOM), nitrite, and alkalinity) on ozone (O(3)) decomposition and subsequent removal of 31 organic contaminants including endocrine disrupting compounds, pharmaceuticals, and personal care products. The O(3) dose was normalized based upon total organic carbon (TOC) and nitrite to allow comparison between the different wastewaters with respect to O(3) decomposition. EfOM with higher molecular weight components underwent greater transformation, which corresponded to increased O(3) decomposition when compared on a TOC basis. Hydroxyl radical (()OH) exposure, measured by parachlorobenzoic acid (pCBA), showed that limited ()OH was available for contaminant destruction during the initial stage of O(3) decomposition (t<30s) due to the effect of the scavenging by the water quality. Advanced oxidation using O(3) and hydrogen peroxide did not increase the net production of ()OH compared to O(3) under the conditions studied. EfOM reactivity impacted the removal of trace contaminants when evaluated based on the O(3):TOC ratio. Trace contaminants with second order reaction rate constants with O(3)(k(O)(3))>10(5)M(-1)s(-1) and ()OH (k(OH))>10(9)M(-1)s(-1), including carbamazepine, diclofenac, naproxen, sulfamethoxazole, and triclosan, were >95% removed independent of water quality when the O(3) exposure (integralO(3)t) was measurable (0-0.8mgmin/L). O(3) exposure would be a conservative surrogate to assess the removal of trace contaminants that are fast-reacting with O(3). Removal of contaminants with k(O)(3) < 10M(-1)S(-1) , and k(OH)>10(9)M(-1)s(-1), including atrazine, iopromide, diazepam, and ibuprofen, varied when O(3) exposure could not be measured, and appeared to be dependent upon the compound specific k(OH). Atrazine, diazepam, ibuprofen and iopromide provided excellent linear correlation with pCBA (R(2)>0.86) making them good

  11. Assessing chironomid deformities in field- and laboratory-exposed organisms from organic- and metal-contaminated sediments

    SciTech Connect

    Canfield, T.J.; Kemble, N.E.; Ingersoll, C.G.

    1994-12-31

    Benthic invertebrate samples were collected from three Great Lakes harbors classified as Areas of concern (AOC) and from the Clark Fork River Superfund Site (CFR) in Montana. Contamination consists of organic and inorganic contaminants at the AOC sites and primarily heavy metal tailings and mining wastes in the CFR sites. Samples were collected with a ponar grab sampler from stations in Indiana Harbor, IN (1989, n = 7), the Buffalo River, NY (1989, n = 10), the Saginaw River, MI (1989, n = 7; 1990, n = 7), and the Clark Fork River (1991, n = 13). Compared to literature values for incidence of deformities in uncontaminated sediments, frequency of Chironomid mouthpart deformities was significantly greater at most stations sampled from the AOC sites. In contrast, only a few stations sampled from the CFR sites had significantly greater incidence of mouthpart deformities. Occurrence of mouthpart deformities ranged from 0 to 100% at the stations from the AOC`s and from 0 to 18% at the CFR stations. These mouthpart deformities in Chironomus riparius laboratory exposures to contaminated sediments from all AOC and CFR sites were evaluated and compared to frequencies found in field collected samples. Preliminary analysis indicates that frequency of mouthpart deformities from laboratory exposed chironomids are generally lower than those found in field collected samples.

  12. Contaminants and microorganisms in Dutch organic food products: a comparison with conventional products.

    PubMed

    Hoogenboom, L A P; Bokhorst, J G; Northolt, M D; van de Vijver, L P L; Broex, N J G; Mevius, D J; Meijs, J A C; Van der Roest, J

    2008-10-01

    Organic products were analysed for the presence of contaminants, microorganisms and antibiotic resistance and compared with those from conventional products. No differences were observed in the Fusarium toxins deoxynivalenol and zearalenone in organic and conventional wheat, during both a dry period and a very wet period which promoted the production of these toxins. Nitrate levels in head lettuce produced organically in the open field were much lower than those in conventional products. In iceberg lettuce and head lettuce from the greenhouse, no differences were detected. Organically produced carrots contained higher nitrate levels than conventional products. Both organic and conventional products contained no residues of non-polar pesticides above the legal limits, although some were detected in conventional lettuce. Organic products contained no elevated levels of heavy metals. Salmonella was detected in 30% of pig faeces samples obtained from 30 organic farms, similar to the incidence at conventional farms. At farms that switched to organic production more then 6 years ago no Salmonella was detected, with the exception of one stable with young pigs recently purchased from another farm. No Salmonella was detected in faeces at the nine farms with organic broilers, and at one out of ten farms with laying hens. This is comparable with conventional farms where the incidence for Salmonella lies around 10%. Campylobacter was detected in faeces at all organic broiler farms, being much higher than at conventional farms. One of the most remarkable results was the fact that faeces from organic pigs and broilers showed a much lower incidence of antibiotic resistant bacteria, except for Campylobacter in broilers. It is concluded that the organic products investigated scored as equally well as conventional products with regard to food safety and at the same time show some promising features with respect to antibiotic resistance.

  13. Quantification of maternal offloading of organic contaminants in elasmobranchs using the histotrophic round stingray (Urobatis halleri) as a model.

    PubMed

    Lyons, Kady; Lowe, Christopher G

    2013-01-01

    Maternal offloading is one route by which young animals may accumulate persistent organic pollutants, such as dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs), but has not been well documented in elasmobranchs despite their propensity to accumulate high concentrations of contaminants. Using the round stingray (Urobatis halleri) as a coastal elasmobranch model, we examined maternal offloading processes at two stages in the stingray's entire reproductive cycle. Post-ovulated and near-term pregnant female stingrays were sampled from southern California, and organic contaminants were measured in the ova and embryonic tissues and compared to concentrations measured in corresponding female livers to determine route and extent of transfer. Total organic contaminant loads measured in ovulated eggs were about two times lower than loads measured in embryos (p < 0.001) indicating mothers have the ability to transfer contaminants throughout pregnancy. Contaminant loads measured in pups showed a positive relationship with mother's contaminant concentrations (p < 0.001); however, mothers offloaded relatively low percentages (1.5 ± 1.7%) of their total contaminant load using contaminants measured in the liver as a proxy. However, histotrophy is only one form of supplemental provisioning utilized by elasmobranchs and variation in reproductive modes likely influences the extent to which female elasmobranchs may maternally offload contaminants. PMID:24073960

  14. Mechanistic approach to multi-element isotope modeling of organic contaminant degradation.

    PubMed

    Jin, Biao; Rolle, Massimo

    2014-01-01

    We propose a multi-element isotope modeling approach to simultaneously predict the evolution of different isotopes during the transformation of organic contaminants. The isotopic trends of different elements are explicitly simulated by tracking position-specific isotopologues that contain the isotopes located at fractionating positions. Our approach is self-consistent and provides a mechanistic description of different degradation pathways that accounts for the influence of both primary and secondary isotope effects during contaminant degradation. The method is particularly suited to quantitatively describe the isotopic evolution of relatively large organic contaminant molecules. For such compounds, an integrated approach, simultaneously considering all possible isotopologues, would be impractical due to the large number of isotopologues. We apply the proposed modeling approach to the degradation of toluene, methyl tert-butyl ether (MTBE) and nitrobenzene observed in previous experimental studies. Our model successfully predicts the multi-element isotope data (both 2D and 3D), and accurately captures the distinct trends observed for different reaction pathways. The proposed approach provides an improved and mechanistic methodology to interpret multi-element isotope data and to predict the extent of multi-element isotope fractionation that goes beyond commonly applied modeling descriptions and simplified methods based on the ratio between bulk enrichment factors or on linear regression in dual-isotope plots.

  15. Mussel watch program for organic contaminants along the Korean coast, 2001-2007.

    PubMed

    Choi, Hee Gu; Moon, Hyo Bang; Choi, Minkyu; Yu, Jun; Kim, Sang Soo

    2010-10-01

    The level and extent of organic contaminants along the Korean coast were estimated through the mussel watch program, established in 2001. Mussels and oysters were collected at 20 sites along the Korean coast in 2001 and at 25 sites from 2002 to 2007. The mussel tissues were analyzed for PCBs, organochlorine presticides, PAHs, BTs, and PCDD/Fs. PCBs, PAHs, BTs, and PCDD/Fs were ubiquitous contaminants along the Korean coast, showing mean detection frequencies of more than 95% over 7 years. The concentrations of organic contaminants in mussels along the Korean coast were relatively low or moderate compared with foreign studies. Concentrations of DDTs, PCBs, and PCDD/Fs were below the action or maximum levels for humans established by USFDA and EU. Elevated concentrations above the 85th percentile were found for PCBs, PAHs, BTs, and PCDD/Fs at sites near industrial complexes or big harbors, for HCHs at sites near non-industrial complexes, and for DDTs at sites near both non-industrial and industrial complexes. Using two nonparametric tests to assess temporal trends, the Spearman test revealed that BTs and PCDD/Fs had significant decreasing trends at four sites (Gwangyang Bay, Cheonsu Bay, Garorym Bay, and the Incheon coast) and at six sites (Hupo coast, Guryongpo coast, eastern part of Geojedo, Gunsan coast, Garorym Bay, and Asan Bay), respectively.

  16. [Physicochemical and microbiological factors influencing the bioavailability of organic contaminants in subsoils

    SciTech Connect

    Not Available

    1992-12-31

    We report progress in elucidating the microbiological variables important in determining the relative success of bacteria in utilizing soil-sorbed contaminants. Two bacterial species, Pseudomonas putida (ATCC 17484) and an Alcaligenes sp. isolated from petroleum contaminated soil are known to differ markedly in their ability to utilize soil-sorbed napthalene based on a kinetic comparison of their capability of naphthalene mineralization in soil-containing and soil-free systems. The kinetic analysis led us to conclude that strain 17484 had direct access to naphthalene present in a labile sorbed state which promoted the rapid desorption of naphthalene from the non-labile phase. Conversely, both the rate and extent of naphthalene mineralization by strain NP-Alk suggested that this organism had access only to naphthalene in solution. Desorption was thus limited and the efficiency of total naphthalene removal from these soil slurries was poor. These conclusions were based on the average activities of cells in soil slurries without regard for the disposition of the organisms with respect to the sorbent. Since both organisms degrade naphthalene by apparently identical biochemical pathways, have similar enzyme kinetic properties, and are both motile, gram negative organisms, we undertook a series of investigations to gain a better understanding of what microbiological properties were important in bioavailability.

  17. Mitigation of the impact of terrestrial contamination on organic measurements from the Mars Science Laboratory.

    PubMed

    ten Kate, Inge L; Canham, John S; Conrad, Pamela G; Errigo, Therese; Katz, Ira; Mahaffy, Paul R

    2008-06-01

    The objective of the 2009 Mars Science Laboratory (MSL), which is planned to follow the Mars Exploration Rovers and the Phoenix lander to the surface of Mars, is to explore and assess quantitatively a site on Mars as a potential habitat for present or past life. Specific goals include an assessment of the past or present biological potential of the target environment and a characterization of its geology and geochemistry. Included in the 10 investigations of the MSL rover is the Sample Analysis at Mars (SAM) instrument suite, which is designed to obtain trace organic measurements, measure water and other volatiles, and measure several light isotopes with experiment sequences designed for both atmospheric and solid-phase samples. SAM integrates a gas chromatograph, a mass spectrometer, and a tunable laser spectrometer supported by sample manipulation tools both within and external to the suite. The sub-part-per-billion sensitivity of the suite for trace species, particularly organic molecules, along with a mobile platform that will contain many kilograms of organic materials, presents a considerable challenge due to the potential for terrestrial contamination to mask the signal of martian organics. We describe the effort presently underway to understand and mitigate, wherever possible within the resource constraints of the mission, terrestrial contamination in MSL and SAM measurements.

  18. Mitigation of the impact of terrestrial contamination on organic measurements from the Mars Science Laboratory.

    PubMed

    ten Kate, Inge L; Canham, John S; Conrad, Pamela G; Errigo, Therese; Katz, Ira; Mahaffy, Paul R

    2008-06-01

    The objective of the 2009 Mars Science Laboratory (MSL), which is planned to follow the Mars Exploration Rovers and the Phoenix lander to the surface of Mars, is to explore and assess quantitatively a site on Mars as a potential habitat for present or past life. Specific goals include an assessment of the past or present biological potential of the target environment and a characterization of its geology and geochemistry. Included in the 10 investigations of the MSL rover is the Sample Analysis at Mars (SAM) instrument suite, which is designed to obtain trace organic measurements, measure water and other volatiles, and measure several light isotopes with experiment sequences designed for both atmospheric and solid-phase samples. SAM integrates a gas chromatograph, a mass spectrometer, and a tunable laser spectrometer supported by sample manipulation tools both within and external to the suite. The sub-part-per-billion sensitivity of the suite for trace species, particularly organic molecules, along with a mobile platform that will contain many kilograms of organic materials, presents a considerable challenge due to the potential for terrestrial contamination to mask the signal of martian organics. We describe the effort presently underway to understand and mitigate, wherever possible within the resource constraints of the mission, terrestrial contamination in MSL and SAM measurements. PMID:18558810

  19. Coupled Geochemical and Reactive Transport Modeling of Organic Contaminants in a Pyrite-Rich Aquifer

    NASA Astrophysics Data System (ADS)

    Sarioglu, S. M.; Copty, N. K.

    2004-12-01

    Although pH is recognized as a key factor influencing bacterial activity, existing groundwater transport models generally do not directly account for the effect of pH on the biodegradation of organic compounds. The purpose of this study is to develop a coupled reactive transport and geochemical model that explicitly incorporates the effect of spatial and temporal variations of the pH on the biodegradation of organic contaminants. The model consists of two modules: a transport module and a geochemical module. The transport module uses a Crank-Nicholson finite-difference formulation to solve the groundwater flow and transport equations for the hydrocarbon, dissolved oxygen, microbial mass and all reactive groundwater species influencing the hydrocarbon biodegradation and pH distribution. The geochemical module allows for the simulation of both kinetically defined as well as geochemical equilibrium reactions. The governing non-linear system of equations is solved using an iterative multi-step operator-splitting algorithm. Both modules account for heterogeneity in the definition of the hydrogeological and biochemical parameters. For demonstration, the model is applied to a hypothetical pyrite-rich aquifer contaminated with petroleum hydrocarbons. A commonly used practice for the remediation of aquifers contaminated with petroleum hydrocarbons is the delivery of oxygen for the enhanced aerobic biodegradation of the organic contaminant. However, the presence of pyrite may interfere with the intended purpose of the supplied oxygen, leading to undesirable side effects. Specifically, oxygen readily reacts with the sulfide minerals leading to depletion of oxygen and acidification of the subsurface environment and, subsequently, the inadvertent inhibition of the microbial activity. The developed coupled geochemical and reactive transport model is used to quantify these processes and assess the dominance of the various chemical reactions. Both abiotic and biotic pyrite

  20. Contribution of microorganisms to non-extractable residue formation from biodegradable organic contaminants in soil

    NASA Astrophysics Data System (ADS)

    Nowak, K. M.; Girardi, C.; Miltner, A.; Schäffer, A.; Kästner, M.

    2012-04-01

    Biodegradation of organic contaminants in soil is actually understood as their transformation into various primary metabolites, microbial biomass, mineralisation products and non-extractable residues (NER). NER are generally considered to be composed of parent compounds or primary metabolites with hazardous potential. Up to date, however, their chemical composition remains still unclear. Studies on NER formation are limited to quantitative analyses in soils or to simple humic acids-contaminant systems. However, in the case of biodegradable organic compounds, NER may also contain microbial biomass components, e.g. fatty acids (FA) and amino acids (AA). After cell death, these biomolecules are incorporated into soil organic matter (SOM) and stabilised, ultimately forming biogenic residues which are not any more extractable. We investigated the incorporation of the 13C-label into FA and AA and their fate during biodegradation experiments in soil with isotope-labelled 2,4-dichlorophenoxyacetic acid (13C6-2,4-D) and ibuprofen (13C6-ibu) as model organic contaminants. Our study proved for the first time that nearly all NER formed from 13C6-2,4-D and 13C6-ibu in soil derived from harmless microbial biomass components stabilised in SOM. 13C-FA and 13C-AA contents in the living microbial biomass fraction decreased over time and these components were continuously incorporated into the non-living SOM pool in biotic experiments with 13C6-2,4-D and 13C6-ibu. The 13C-AA in the non-living SOM were surprisingly stable from day 32 (13C6-2,4-D) and 58 (13C6-ibu) until the end of incubation. We also studied the transformation of 13C6-2,4-D and 13C6-ibu into NER in the abiotic soil experiments. In these experiments, the total NER contents were much lower than in the corresponding biotic experiments. The absence of labelled biomolecules in the NER fraction in abiotic soils demonstrated that they consist of the potentially hazardous parent compounds and / or their metabolites. Biogenic

  1. Temporal and spatial variation of atmospherically deposited organic contaminants at high elevation in Yosemite National Park, California, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atmospherically deposited organic contaminants in the Sierra Nevada Mountains of California, USA, have exceeded some thresholds of concern, yet the distributions of contaminants in the mountains are not well known and there is little knowledge of temporal variation. The present study, (1) evaluated...

  2. [Contamination of soil with geohelminth eggs on vegetable organic farms in the Lublin voivodeship, Poland].

    PubMed

    Kłapeć, Teresa

    2009-01-01

    Organic farming, despite being more difficult and labour consuming than traditional farming, gains increasingly more followers among farmers. Currently in Poland there are approximately 10 000 organic farms. Pure, uncontaminated soil in the Lublin voivodeship makes this area an ideal location for organic agriculture production. In 2006-2007, 102 soil samples were examined from 40 organic farms specializing in vegetables and berries. Farms for the study were selected by ecology- and food-production specialists from the Lublin Agriculture Advisory Centre in Końskowola. The following plants were cultivated on the farms examined: berry-bearing plants, carrots, parsley, zucchini, cabbage, lettuce, cucumbers, cauliflowers, leeks, onions, kidney beans, beetroots, potatoes, pumpkins, broad beans, rhubarb and herbs. The presently reported parasitological survey was performed on 102 soil samples. Each sample consisted of 100 g of soil and the methodology followed that of the Polish Standard PN-Z-19000-4 (flotation method by Quinn et al.). The survey yielded eggs of parasites representing genera: Ascaris, Trichuris and Toxocara. Contamination with eggs of intestinal parasites was noted in 43 (42.16%) soil samples. Toxocara spp. eggs were found in 24 samples (55.81%). Eggs of Ascaris spp. were detected in 18 samples (41.86%) while eggs of Trichuris spp were present in one sample (2.32%). In total, 29 eggs of Toxocara spp., 19 eggs of Ascaris spp., and 1 egg of Trichuris spp. were found. The largest amount of soil for examination was taken across the plantations of berry-bearing plants - 57 samples. In the group examined, plantations of raspberries and strawberries dominated. The soil was contaminated with the eggs of Toxocara spp. and Ascaris spp. No eggs of Trichuris spp. were detected. The presence of eggs of intestinal parasites in soil poses a threat of geohelminthoses to people who eat contaminated fresh fruits and vegetables. PMID:20209816

  3. An overview of time trends in organic contaminant concentrations in marine mammals: going up or down?

    PubMed

    Law, Robin J

    2014-05-15

    In this article I review recent trends reported in the literature from 2008 to date for organic contaminant concentrations in marine mammal tissues worldwide, in order to get an idea of where we stand currently in relation to the control of hazardous substances. For many contaminants which have been subject to regulation regarding their production and use (e.g. organochlorine pesticides, PBDE and HBCD flame retardants, butyltins) trends are downwards. For perfluorinated compounds, trends are more mixed. For dioxins, furans and dioxin-like CBs, there are no recent data, for either concentrations or trends. For CBs overall, earlier downward trends in concentration in UK harbour porpoises following regulation beginning in the 1980s have stalled, and remain at toxicologically significant levels. This raises concerns for killer whales and bottlenose dolphins who, because of their larger size and greater bioaccumulation potential, have higher levels still, often far above accepted toxicological threshold values. PMID:24703807

  4. [Characteristics of gaseous pollutants distribution during remedial excavation at a volatile organic compound contaminated site].

    PubMed

    Gan, Ping; Yang, Yue-Wei; Fang, Zeng-Qiang; Guo, Shu-Qian; Yu, Yan; Jia, Jian-Li

    2013-12-01

    Volatile and semi-volatile organic compounds (VOCs/SVOCs) are commonly identified contaminants in industrial contaminated sites in China. VOCs migrate easily in the environment due to their relatively high volatilities. When disturbed during excavation, for example, VOCs in the soil release to the air in high concentrations within relatively short period of time, joepodizing the health of the sorrounding population, if not appropriately protected. In this study, distribution of gas phase VOCs was monitored during excavation of a site remediation project, using a combined method of field testing instrument and gas phase sampling tubes. Monitoring results indicated that gas phase concentration decreased with distance, exhibiting an alternating peak-and-valley pattern in the down-wind direction. The monitoring results could be stimulated using Gaussian Puff Model. Remediation site health and safety zoning method was developed combining appropriate workplace health and safety air limits and site monitoring results. Personal protection measures deemed appropriated for each safety zone were proposed.

  5. Methods to Assess Bioavailability of Hydrophobic Organic Contaminants: Principles, Operations, and Limitations

    PubMed Central

    Cui, Xinyi; Mayer, Philipp; Gan, Jay

    2013-01-01

    Many important environmental contaminants are hydrophobic organic contaminants (HOCs), which include PCBs, PAHs, PBDEs, DDT and other chlorinated insecticides, among others. Owing to their strong hydrophobicity, HOCs have their final destination in soil or sediment, where their ecotoxicological effects are closely regulated by sorption and thus bioavailability. The last two decades has seen a dramatic increase in research efforts in developing and applying partitioning based methods and biomimetic extractions for measuring HOC bioavailability. However, the many variations of both analytical methods and associated measurement endpoints are often a source of confusion for users. In this review, we distinguish the most commonly used analytical approaches based on their measurement objectives, and illustrate their practical operational steps, strengths and limitations using simple flowcharts. This review may serve as guidance for new users on the selection and use of established methods, and a reference for experienced investigators to identify potential topics for further research. PMID:23064200

  6. Petroleum refinery secondary effluent polishing using freezing processes--toxicity and organic contaminant removal.

    PubMed

    Gao, W; Smith, D W; Habib, M

    2008-06-01

    A petroleum refinery secondary effluent was treated using two freezing techniques--spray freezing and unidirectional downward freezing (UDF). The freezing processes were effective to remove toxicity and total organic carbon (TOC)- and chemical oxygen demand (COD)-causing materials in the effluent. Agitation of the liquid during UDF significantly improved the impurity separation efficiency; 85 to 96% removal of TOC and COD was achieved without any pretreatment and freezing only 70% of the feed water. The treatment efficiency of the spray freezing was at the same level as that of UDF without mixing. The spray ice with longer storage time released more contaminants with early meltwater. The initial contaminant concentration of the feed water and the freezing temperatures (-10 degrees C and -25 degrees C) had no significant influence on the treatment efficiency. A small fluctuation in effluent TOC concentration caused a dramatic change in effluent toxicity (Microtox). The effective concentration (EC20) (Microtox) was effective in detecting effluent toxicity. PMID:18686927

  7. An overview of time trends in organic contaminant concentrations in marine mammals: going up or down?

    PubMed

    Law, Robin J

    2014-05-15

    In this article I review recent trends reported in the literature from 2008 to date for organic contaminant concentrations in marine mammal tissues worldwide, in order to get an idea of where we stand currently in relation to the control of hazardous substances. For many contaminants which have been subject to regulation regarding their production and use (e.g. organochlorine pesticides, PBDE and HBCD flame retardants, butyltins) trends are downwards. For perfluorinated compounds, trends are more mixed. For dioxins, furans and dioxin-like CBs, there are no recent data, for either concentrations or trends. For CBs overall, earlier downward trends in concentration in UK harbour porpoises following regulation beginning in the 1980s have stalled, and remain at toxicologically significant levels. This raises concerns for killer whales and bottlenose dolphins who, because of their larger size and greater bioaccumulation potential, have higher levels still, often far above accepted toxicological threshold values.

  8. Trends of chlorinated organic contaminants in Great Lakes trout and walleye from 1970-1998

    USGS Publications Warehouse

    Hickey, J.P.; Batterman, S.A.; Chernyak, S.M.

    2006-01-01

    Levels of chlorinated organic contaminants in predator fish have been monitored annually in each of the Great Lakes since the 1970s. This article updates earlier reports with data from 1991 to 1998 for lake trout (Salvelinus namaycush) and (Lake Erie only) walleye (Sander vitreus) to provide a record that now extends nearly 30 years. Whole fish were analyzed for a number of industrial contaminants and pesticides, including polychlorinated biphenyls (PCBs), dichloro-diphenyl-trichloroethane (DDT), dieldrin, toxaphene, and mirex, and contaminant trends were quantified using multicompartment models. As in the past, fish from Lakes Michigan, Ontario, and Huron have the highest levels of PCBs, DDT, and dieldrin; Superior has the highest levels of toxaphene; and Ontario has the highest levels of mirex. In the period after curtailment of chemical use, concentrations rapidly decreased, represented by relatively short half-lives from approximately 1 to 9 years. Although trends depend on both the contaminant and the lake, in many cases the rate of decline has been decreasing, and concentrations are gradually approaching an irreducible concentration. For dioxin-like PCBs, levels have not been decreasing during the most recent 5-year period (1994 to 1998). In some cases, the year-to-year variation in contaminant levels is large, mainly because of food-web dynamics. Although this variation sometimes obscures long-term trends, the general pattern of a rapid decrease followed by slowing or leveling-off of the downward trend seems consistent across the Great Lakes, and future improvements of the magnitude seen in the 1970s and early 1980s likely will take much longer.

  9. A national-scale assessment of micro-organic contaminants in groundwater of England and Wales.

    PubMed

    Manamsa, Katya; Crane, Emily; Stuart, Marianne; Talbot, John; Lapworth, Dan; Hart, Alwyn

    2016-10-15

    A large variety of micro-organic (MO) compounds is used in huge quantities for a range of purposes (e.g. manufacturing, food production, healthcare) and is now being frequently detected in the aquatic environment. Interest in the occurrence of MO contaminants in the terrestrial and aquatic environments continues to grow, as well as in their environmental fate and potential toxicity. However, the contamination of groundwater resources by MOs has a limited evidence base compared to other freshwater resources. Of particular concern are newly 'emerging contaminants' such as pharmaceuticals and lifestyle compounds, particularly those with potential endocrine disrupting properties. While groundwater often has a high degree of protection from pollution due to physical, chemical and biological attenuation processes in the subsurface compared to surface aquatic environments, trace concentrations of a large range of compounds are still detected in groundwater and in some cases may persist for decades due to the long residence times of groundwater systems. This study provides the first national-scale assessment of micro-organic compounds in groundwater in England and Wales. A large set of monitoring data was analysed to determine the relative occurrence and detected concentrations of different groups of compounds and to determine relationships with land-use, aquifer type and groundwater vulnerability. MOs detected including emerging compounds such as caffeine, DEET, bisphenol A, anti-microbial agents and pharmaceuticals as well as a range of legacy contaminants including chlorinated solvents and THMs, petroleum hydrocarbons, pesticides and other industrial compounds. There are clear differences in MOs between land-use types, particularly for urban-industrial and natural land-use. Temporal trends of MO occurrence are assessed but establishing long-term trends is not yet possible. PMID:27073165

  10. Depositional history of organic contaminants on the Palos Verdes Shelf, California

    USGS Publications Warehouse

    Eganhouse, R.P.; Pontolillo, J.

    2000-01-01

    During more than 60 years, sedimentation on the Palos Verdes Shelf has been dominated by time-varying inputs of municipal wastewater from the Los Angeles County Sanitation Districts (LACSD) and debris from the Portuguese Bend Landslide (PBL). The present study examines the depositional history of wastewater-derived organic contaminants at a site approximately 6-8 km downcurrent from the outfall system. Sediments at this location are impacted by contributions from both sources, but the relative influence of the sources has changed over time. Two classes of hydrophobic organic contaminants (chlorinated hydrocarbons, long-chain alkylbenzenes) were determined in sediment cores collected in 1981 and 1992. Using molecular stratigraphy, we determined average sedimentation rates (cm/year) and mass accumulation rates (g cm-2 year-1) for the following periods: 1955-1965, 1965-1971, 1971-1981 and 1981-1992. The results show that sedimentation and mass accumulation rates increased from 1955 to 1971 and decreased from 1971 to 1981. These trends are consistent with historical information on the emission of suspended solids from the outfall system, indicating that the discharge of wastes dominated sedimentation at the site during this period. In the 1980s and early 1990s, however, mass accumulation rates increased in spite of continually decreasing emissions of wastewater solids. Several lines of evidence indicate that this increase was due to mobilization of debris from the PBL during and after unusually strong winter storms in the 1980s. As a result, heavily contaminated sediments deposited during the years of greatest waste emissions (i.e. 1950-1970) have been buried to greater sub-bottom depths, thereby reducing their availability for mobilization to the overlying water column. These results highlight the dynamic nature of sedimentation in contaminated coastal ecosystems and its importance to the long-term fate and effects of toxic substances.

  11. Organic Nutrients and Contaminants In Subsistence Species of Alaska: Concentrations and Relationship To Food Preparation Method

    PubMed Central

    Moses, Sara K.; Whiting, Alex V.; Muir, Derek C.G.; Wang, Xiaowa; O'Hara, Todd M.

    2009-01-01

    Objectives To determine nutrient and contaminant concentrations, document concentration changes related to common preparation methods and provide a basic risk-benefit analysis for select subsistence foods consumed by residents of Kotzebue, Alaska. Study design Eleven organic nutrients and 156 persistent organic pollutants (POPs) were measured in foods derived from spotted seals and sheefish. Methods Nutrients in foodstuffs were compared to Daily Recommended Intake criteria. POPs were compared to Tolerable Daily Intake Limits (TDIL). Results Cooking, as well as absence/presence of skin during sheefish processing, altered nutrient and contaminant concentrations in seals and fish. Sheefish muscle and seal blubber were particularly rich in omega-3 fatty acids and seal liver in vitamin A. Seal liver exceeded the recommended upper limit for vitamin A. POP contribution to TDIL was <25% in all tissues except blubber, in which 4 POPs were present at >25% TDIL. No POPs exceeded TDIL in a serving of any tissue studied. The most prominent concerns identified were levels of vitamin A in spotted seal liver and certain POPs in blubber, warranting consideration when determining how much and how often these foods should be consumed. Conclusions Preparation methods altering tissues from their raw state significantly affect nutrient and contaminant concentrations, thus direct evaluation of actual food items is highly recommended to determine risk-benefits ratios of traditional diets. Traditional foods provide essential nutrients with very limited risk from contaminants. We encourage the consumption of traditional foods and urge public health agencies to develop applicable models to assess overall food safety and quality. PMID:19917188

  12. A national-scale assessment of micro-organic contaminants in groundwater of England and Wales.

    PubMed

    Manamsa, Katya; Crane, Emily; Stuart, Marianne; Talbot, John; Lapworth, Dan; Hart, Alwyn

    2016-10-15

    A large variety of micro-organic (MO) compounds is used in huge quantities for a range of purposes (e.g. manufacturing, food production, healthcare) and is now being frequently detected in the aquatic environment. Interest in the occurrence of MO contaminants in the terrestrial and aquatic environments continues to grow, as well as in their environmental fate and potential toxicity. However, the contamination of groundwater resources by MOs has a limited evidence base compared to other freshwater resources. Of particular concern are newly 'emerging contaminants' such as pharmaceuticals and lifestyle compounds, particularly those with potential endocrine disrupting properties. While groundwater often has a high degree of protection from pollution due to physical, chemical and biological attenuation processes in the subsurface compared to surface aquatic environments, trace concentrations of a large range of compounds are still detected in groundwater and in some cases may persist for decades due to the long residence times of groundwater systems. This study provides the first national-scale assessment of micro-organic compounds in groundwater in England and Wales. A large set of monitoring data was analysed to determine the relative occurrence and detected concentrations of different groups of compounds and to determine relationships with land-use, aquifer type and groundwater vulnerability. MOs detected including emerging compounds such as caffeine, DEET, bisphenol A, anti-microbial agents and pharmaceuticals as well as a range of legacy contaminants including chlorinated solvents and THMs, petroleum hydrocarbons, pesticides and other industrial compounds. There are clear differences in MOs between land-use types, particularly for urban-industrial and natural land-use. Temporal trends of MO occurrence are assessed but establishing long-term trends is not yet possible.

  13. Surfactant-modified zeolites as permeable barriers to organic and inorganic groundwater contaminants

    SciTech Connect

    Bowman, R.S.; Sullivan, E.J.

    1995-10-01

    We have shown in laboratory experiments that natural zeolites treated with hexadecyltrimethylammonium (HDTMA) are effective sorbents for nonpolar organics, inorganic cations, and inorganic anions. Due to their low cost ({approximately}$0.75/kg) and granular nature, HDTMA-zeolites appear ideal candidates for reactive, permeable subsurface barriers. The HDTMA-zeolites are stable over a wide range of pH (3-13), ionic strength (1 M Cs{sup +} or Ca{sup 2+}), and in organic solvents. Surfactant-modified zeolites sorb nonpolar organics (benzene, toluene, xylene, chlorinated aliphatics) via a partitioning mechanism, inorganic cations (Pb{sup 2+}) via ion exchange and surface complexation, and inorganic anions (CrO{sub 4}{sup 2-}, SeO{sub 4}{sup 2-}, SO{sub 4}{sup 2-}) via surface precipitation.The goal of this work is to demonstrate the use of surfactant-modified zeolite as a permeable barrier to ground water contaminants.

  14. POLANYI-BASED MODELS FOR THE COMPETITIVE SORPTION OF LOW-POLARITY ORGANIC CONTAMINANTS ON A NATURAL SORBENT. (R825406)

    EPA Science Inventory

    The development of appropriate equilibrium sorption relationships for anthropogenic organic contaminants with soils and sediments is essential to predicting the extents and rates of solid-water interactions in the environment. In this context, we previously reported results that ...

  15. EMERGING TECHNOLOGY BULLETIN: PROCESS FOR THE TREATMENT OF VOLATILE ORGANIC CARBON AND HEAVY-METAL- CONTAMINATED SOIL - INTERNATIONAL TECHNOLOGY CORPORATION

    EPA Science Inventory

    The batch steam distillation and metal extraction treatment process is a two-stage system that treats soils contaminated with organics and inorganics. This system uses conventional, readily available process equipment, and does not produce hazardous combustion products. Hazar...

  16. Constructed Wetlands for Treatment of Organic and Engineered Nanomaterial Contaminants of Emerging Concerns (WaterRF Report 4334)

    EPA Science Inventory

    The goal of this project was to determine hydraulic and carbon loading rates for constructed wetlands required for achieving different levels of organic and nanomaterial contaminants of emerging concern (CECs) removal in constructed wetlands. Specific research objectives included...

  17. Comparison of Passive Samplers for Monitoring Dissolved Organic Contaminants in Water Column Deployments (SETAC Europe 22nd Annual Meeting)

    EPA Science Inventory

    Nonionic organic contaminants (NOCs) are difficult to measure in the water column due to their inherent chemical properties resulting in low water solubility and high particle activity. Traditional sampling methods require large quantities of water to be extracted and interferen...

  18. Comparison of Passive Samplers for Monitoring Dissolved Organic Contaminants in Water Column Deployments NAC/SETAC 2012

    EPA Science Inventory

    Nonionic organic contaminants (NOCs) are difficult to measure in the water column due to their inherent chemical properties resulting in low water solubility and high particle activity. Traditional sampling methods require large quantities of water to be extracted and interferen...

  19. Visualising the equilibrium distribution and mobility of organic contaminants in soil using the chemical partitioning space.

    PubMed

    Wong, Fiona; Wania, Frank

    2011-06-01

    Assessing the behaviour of organic chemicals in soil is a complex task as it is governed by the physical chemical properties of the chemicals, the characteristics of the soil as well as the ambient conditions of the environment. The chemical partitioning space, defined by the air-water partition coefficient (K(AW)) and the soil organic carbon-water partition coefficient (K(OC)), was employed to visualize the equilibrium distribution of organic contaminants between the air-filled pores, the pore water and the solid phases of the bulk soil and the relative importance of the three transport processes removing contaminants from soil (evaporation, leaching and particle erosion). The partitioning properties of twenty neutral organic chemicals (i.e. herbicides, pharmaceuticals, polychlorinated biphenyls and volatile chemicals) were estimated using poly-parameter linear free energy relationships and superimposed onto these maps. This allows instantaneous estimation of the equilibrium phase distribution and mobility of neutral organic chemicals in soil. Although there is a link between the major phase and the dominant transport process, such that chemicals found in air-filled pore space are subject to evaporation, those in water-filled pore space undergo leaching and those in the sorbed phase are associated with particle erosion, the partitioning coefficient thresholds for distribution and mobility can often deviate by many orders of magnitude. In particular, even a small fraction of chemical in pore water or pore air allows for evaporation and leaching to dominate over solid phase transport. Multiple maps that represent soils that differ in the amount and type of soil organic matter, water saturation, temperature, depth of surface soil horizon, and mineral matters were evaluated.

  20. Visualising the equilibrium distribution and mobility of organic contaminants in soil using the chemical partitioning space.

    PubMed

    Wong, Fiona; Wania, Frank

    2011-06-01

    Assessing the behaviour of organic chemicals in soil is a complex task as it is governed by the physical chemical properties of the chemicals, the characteristics of the soil as well as the ambient conditions of the environment. The chemical partitioning space, defined by the air-water partition coefficient (K(AW)) and the soil organic carbon-water partition coefficient (K(OC)), was employed to visualize the equilibrium distribution of organic contaminants between the air-filled pores, the pore water and the solid phases of the bulk soil and the relative importance of the three transport processes removing contaminants from soil (evaporation, leaching and particle erosion). The partitioning properties of twenty neutral organic chemicals (i.e. herbicides, pharmaceuticals, polychlorinated biphenyls and volatile chemicals) were estimated using poly-parameter linear free energy relationships and superimposed onto these maps. This allows instantaneous estimation of the equilibrium phase distribution and mobility of neutral organic chemicals in soil. Although there is a link between the major phase and the dominant transport process, such that chemicals found in air-filled pore space are subject to evaporation, those in water-filled pore space undergo leaching and those in the sorbed phase are associated with particle erosion, the partitioning coefficient thresholds for distribution and mobility can often deviate by many orders of magnitude. In particular, even a small fraction of chemical in pore water or pore air allows for evaporation and leaching to dominate over solid phase transport. Multiple maps that represent soils that differ in the amount and type of soil organic matter, water saturation, temperature, depth of surface soil horizon, and mineral matters were evaluated. PMID:21637880

  1. The characterization of organic contaminants during the development of the Space Station water reclamation and management system

    NASA Technical Reports Server (NTRS)

    Cole, H.; Habercom, M.; Crenshaw, M.; Johnson, S.; Manuel, S.; Martindale, W.; Whitman, G.; Traweek, M.

    1991-01-01

    Examples of the application of various methods for characterizing samples for alcohols, fatty acids, detergents, and volatile/semivolatile basic, neutral, and phenolic acid contaminants are presented. Data, applications, and interpretations are given for a variety of methods including sample preparation/cleanup procedures, ion chromatography, and gas chromatography with various detectors. Summaries of the major organic contaminants that contribute to the total organic carbon content are presented.

  2. Electrokinetic-enhanced bioremediation of organic contaminants: a review of processes and environmental applications.

    PubMed

    Gill, R T; Harbottle, M J; Smith, J W N; Thornton, S F

    2014-07-01

    There is current interest in finding sustainable remediation technologies for the removal of contaminants from soil and groundwater. This review focuses on the combination of electrokinetics, the use of an electric potential to move organic and inorganic compounds, or charged particles/organisms in the subsurface independent of hydraulic conductivity; and bioremediation, the destruction of organic contaminants or attenuation of inorganic compounds by the activity of microorganisms in situ or ex situ. The objective of the review is to examine the state of knowledge on electrokinetic bioremediation and critically evaluate factors which affect the up-scaling of laboratory and bench-scale research to field-scale application. It discusses the mechanisms of electrokinetic bioremediation in the subsurface environment at different micro and macroscales, the influence of environmental processes on electrokinetic phenomena and the design options available for application to the field scale. The review also presents results from a modelling exercise to illustrate the effectiveness of electrokinetics on the supply electron acceptors to a plume scale scenario where these are limiting. Current research needs include analysis of electrokinetic bioremediation in more representative environmental settings, such as those in physically heterogeneous systems in order to gain a greater understanding of the controlling mechanisms on both electrokinetics and bioremediation in those scenarios.

  3. Impact of plastics on fate and transport of organic contaminants in landfills.

    PubMed

    Saquing, Jovita M; Saquing, Carl D; Knappe, Detlef R U; Barlaz, Morton A

    2010-08-15

    Factors controlling organic contaminant sorption to common plastics in municipal solid waste were identified. Consumer plastics [drinking water container, prescription drug bottle, soda bottle, disposable cold cup, computer casing, furniture foam, carpet, vinyl flooring, formica sheet] and model polymers [high-density polyethylene (HDPE), medium-density polyethylene, low-density polyethylene, poly(vinyl chloride) (PVC)] were characterized by X-ray diffractometry, differential scanning calorimetry, and elemental analysis. The material characterization was used to interpret batch isotherm and kinetic data. K(p) values describing toluene sorption to rubbery or "soft" polymers could be normalized by the amorphous polymer fraction (f(amorphous)) but not by the organic carbon fraction (f(oc)). Diffusion coefficients (D) describing the uptake rate of toluene by rubbery plastics (HDPE, drinking water container, prescription drug bottle) were similar (D approximately 10(-10) cm(2)/s), indicating that pure HDPE can be used as a model for rubbery plastics. Toluene diffusivity was similar among glassy or "hard" plastics (PVC, soda bottle, computer casing, disposable cold cup; D approximately 10(-12) cm(2)/s) but lower than for rubbery plastics. Plastics in landfills are potential sinks of hydrophobic organic contaminants (HOCs) because of their higher affinity for HOCs compared to lignocellulosic materials and the slow desorption of HOCs from glassy plastics.

  4. Preparation of Silica/Reduced Graphene Oxide Nanosheet Composites for Removal of Organic Contaminants from Water.

    PubMed

    Li, Wen; Liu, Wei; Wang, Haifei; Lu, Wensheng

    2016-06-01

    Graphene-based composites open up new opportunities as effective adsorbents for the removal of organic contaminants from water. In this article, we report a novel and facile process to synthesize well-dispersed silica/reduced graphene oxide (SiO2/RGO) nanosheet composites. The SiO2/RGO nanosheet composites are prepared through a modified sol-gel process with in situ hydrolysis of tetraethoxysilane (TEOS) on graphene oxide (GO) nanosheet, followed by reduction of GO to graphene. In comparison with the RGO nanosheets, the as-prepared SiO2/RGO nanosheet composites have a larger surface area and good aqueous disperse ability. In addition, the application of SiO2/RGO nanosheet composites was demonstrated on removing organic dyes from water. The SiO2/RGO nanosheet composites show rapid and stable adsorption performance on removal of Methylene Blue (MB) and thionine (TH) from water. It is indicated that the resulting SiO2/RGO composites can be utilized as efficient adsorbents for the removal of organic contaminants from water.

  5. Spatiotemporal characteristics of organic contaminant concentrations and ecological risk assessment in the Songhua River, China.

    PubMed

    Wang, Ce; Cyterski, Mike; Feng, Yujie; Gao, Peng; Sun, Qingfang

    2015-11-01

    To control source pollution and improve water quality, an understanding of the spatiotemporal characteristics of organic contaminant concentrations in affected receiving waters is necessary. The Songhua River in northeast China is the country's third-largest domestic river and loadings of organic contaminants along an industrialized section have made it the focal point of a national pollution reduction plan. In addition to water quality issues, management of the Songhua River basin must also address local economic development, aquatic ecosystem sustainability and political relationships with Russia. In three periods spanning 2006 to 2010, eight polycyclic aromatic hydrocarbons (PAHs) and eight phenols were measured in surface waters at ten monitoring sites along the river. A generalized linear model (GLM) was used to characterize water quality at different sites and time periods. Chemical concentrations of the organic compounds showed significant sinusoidal seasonal patterns and the concentrations declined significantly from 2006 to 2010, possibly due to management practices designed to control water pollution. A critical body residue analysis showed that water concentrations measured during the winter of 2007 across all monitoring sites, but especially at S1-Shaokou and S2-Songhuajiangcun, presented a high risk for fish species. The spatiotemporal characteristics of water quality and estimated ecological risks shown here add to the body of knowledge to develop policies on industrial output and pollution management strategies for the Songhua River basin. PMID:26442573

  6. Removal of organic wastewater contaminants in septic systems using advanced treatment technologies

    USGS Publications Warehouse

    Wilcox, J.D.; Bahr, J.M.; Hedman, C.J.; Hemming, J.D.C.; Barman, M.A.E.; Bradbury, K.R.

    2009-01-01

    The detection of pharmaceuticals and other organic wastewater contaminants (OWCs) in ground water and surface-water bodies has raised concerns about the possible ecological impacts of these compounds on nontarget organisms. On-site wastewater treatment systems represent a potentially significant route of entry for organic contaminants to the environment. In this study, effluent samples were collected and analyzed from conventional septic systems and from systems using advanced treatment technologies. Six of 13 target compounds were detected in effluent from at least one septic system. Caffeine, paraxanthine, and acetaminophen were the most frequently detected compounds, and estrogenic activity was detected in 14 of 15 systems. The OWC concentrations were significantly lower in effluent after sand filtration (p < 0.01) or aerobic treatment (p < 0.05) as compared with effluent that had not undergone advanced treatment. In general, concentrations in conventional systems were comparable to those measured in previous studies of municipal wastewater treatment plant (WWTP) influent, and concentrations in systems after advanced treatment were comparable to previously measured concentrations in WWTP effluent. These data indicate that septic systems using advanced treatment can reduce OWCs in treated effluent to similar concentrations as municipal WWTPs. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  7. Preparation of Silica/Reduced Graphene Oxide Nanosheet Composites for Removal of Organic Contaminants from Water.

    PubMed

    Li, Wen; Liu, Wei; Wang, Haifei; Lu, Wensheng

    2016-06-01

    Graphene-based composites open up new opportunities as effective adsorbents for the removal of organic contaminants from water. In this article, we report a novel and facile process to synthesize well-dispersed silica/reduced graphene oxide (SiO2/RGO) nanosheet composites. The SiO2/RGO nanosheet composites are prepared through a modified sol-gel process with in situ hydrolysis of tetraethoxysilane (TEOS) on graphene oxide (GO) nanosheet, followed by reduction of GO to graphene. In comparison with the RGO nanosheets, the as-prepared SiO2/RGO nanosheet composites have a larger surface area and good aqueous disperse ability. In addition, the application of SiO2/RGO nanosheet composites was demonstrated on removing organic dyes from water. The SiO2/RGO nanosheet composites show rapid and stable adsorption performance on removal of Methylene Blue (MB) and thionine (TH) from water. It is indicated that the resulting SiO2/RGO composites can be utilized as efficient adsorbents for the removal of organic contaminants from water. PMID:27427624

  8. Impact of plastics on fate and transport of organic contaminants in landfills.

    PubMed

    Saquing, Jovita M; Saquing, Carl D; Knappe, Detlef R U; Barlaz, Morton A

    2010-08-15

    Factors controlling organic contaminant sorption to common plastics in municipal solid waste were identified. Consumer plastics [drinking water container, prescription drug bottle, soda bottle, disposable cold cup, computer casing, furniture foam, carpet, vinyl flooring, formica sheet] and model polymers [high-density polyethylene (HDPE), medium-density polyethylene, low-density polyethylene, poly(vinyl chloride) (PVC)] were characterized by X-ray diffractometry, differential scanning calorimetry, and elemental analysis. The material characterization was used to interpret batch isotherm and kinetic data. K(p) values describing toluene sorption to rubbery or "soft" polymers could be normalized by the amorphous polymer fraction (f(amorphous)) but not by the organic carbon fraction (f(oc)). Diffusion coefficients (D) describing the uptake rate of toluene by rubbery plastics (HDPE, drinking water container, prescription drug bottle) were similar (D approximately 10(-10) cm(2)/s), indicating that pure HDPE can be used as a model for rubbery plastics. Toluene diffusivity was similar among glassy or "hard" plastics (PVC, soda bottle, computer casing, disposable cold cup; D approximately 10(-12) cm(2)/s) but lower than for rubbery plastics. Plastics in landfills are potential sinks of hydrophobic organic contaminants (HOCs) because of their higher affinity for HOCs compared to lignocellulosic materials and the slow desorption of HOCs from glassy plastics. PMID:20704240

  9. Effects of predicted climatic changes on distribution of organic contaminants in brackish water mesocosms.

    PubMed

    Ripszam, M; Gallampois, C M J; Berglund, Å; Larsson, H; Andersson, A; Tysklind, M; Haglund, P

    2015-06-01

    Predicted consequences of future climate change in the northern Baltic Sea include increases in sea surface temperatures and terrestrial dissolved organic carbon (DOC) runoff. These changes are expected to alter environmental distribution of anthropogenic organic contaminants (OCs). To assess likely shifts in their distributions, outdoor mesocosms were employed to mimic pelagic ecosystems at two temperatures and two DOC concentrations, current: 15°C and 4 mg DOCL(-1) and, within ranges of predicted increases, 18°C and 6 mg DOCL(-1), respectively. Selected organic contaminants were added to the mesocosms to monitor changes in their distribution induced by the treatments. OC partitioning to particulate matter and sedimentation were enhanced at the higher DOC concentration, at both temperatures, while higher losses and lower partitioning of OCs to DOC were observed at the higher temperature. No combined effects of higher temperature and DOC on partitioning were observed, possibly because of the balancing nature of these processes. Therefore, changes in OCs' fates may largely depend on whether they are most sensitive to temperature or DOC concentration rises. Bromoanilines, phenanthrene, biphenyl and naphthalene were sensitive to the rise in DOC concentration, whereas organophosphates, chlorobenzenes (PCBz) and polychlorinated biphenyls (PCBs) were more sensitive to temperature. Mitotane and diflufenican were sensitive to both temperature and DOC concentration rises individually, but not in combination. PMID:25710621

  10. Electrokinetic-enhanced bioremediation of organic contaminants: a review of processes and environmental applications.

    PubMed

    Gill, R T; Harbottle, M J; Smith, J W N; Thornton, S F

    2014-07-01

    There is current interest in finding sustainable remediation technologies for the removal of contaminants from soil and groundwater. This review focuses on the combination of electrokinetics, the use of an electric potential to move organic and inorganic compounds, or charged particles/organisms in the subsurface independent of hydraulic conductivity; and bioremediation, the destruction of organic contaminants or attenuation of inorganic compounds by the activity of microorganisms in situ or ex situ. The objective of the review is to examine the state of knowledge on electrokinetic bioremediation and critically evaluate factors which affect the up-scaling of laboratory and bench-scale research to field-scale application. It discusses the mechanisms of electrokinetic bioremediation in the subsurface environment at different micro and macroscales, the influence of environmental processes on electrokinetic phenomena and the design options available for application to the field scale. The review also presents results from a modelling exercise to illustrate the effectiveness of electrokinetics on the supply electron acceptors to a plume scale scenario where these are limiting. Current research needs include analysis of electrokinetic bioremediation in more representative environmental settings, such as those in physically heterogeneous systems in order to gain a greater understanding of the controlling mechanisms on both electrokinetics and bioremediation in those scenarios. PMID:24875868

  11. Adherence of Mycoplasma hyopneumoniae to cell monolayers.

    PubMed

    Zielinski, G C; Young, T; Ross, R F; Rosenbusch, R F

    1990-03-01

    This work was an attempt to develop an in vitro adherence model for Mycoplasma hyopneumoniae, using monolayers of human and porcine lung fibroblasts and porcine kidney cells. Mycoplasma hyopneumoniae grown in Friis mycoplasma broth was radiolabeled with 35[S]-methionine, washed, concentrated, and inoculated on the monolayers. After 15 minutes of centrifugation to facilitate adherence, monolayers were washed 3 times, dissolved with 0.1N NaOH, and suspended in scintillation liquid, and the radioactivity was determined in a liquid scintillation counter. Adherence, measured as a percentage of counts added, varied according to the mycoplasma strain and the cell line used. Comparison of strains J, 144L, and 232 of M hyopneumoniae revealed 7.5 +/- 5.9, 31.9 +/- 13, and 9.6 +/- 5% adherence to porcine kidney cells, respectively. Slightly different, but proportionally the same relationships were obtained with swine or human fibroblasts. Adherence was decreased slightly by repeated washings of the mycoplasma-treated cell monolayers; however, a plateau was reached, indicating irreversibility of the adherence process. Pretreatment of cell monolayers with nonlabeled organisms substantially blocked adherence by labeled organisms. Dilution of labeled organisms resulted in an increased proportion adhering. Therefore, it appears that the adherence was a receptor-dependent event. Treatment of the mycoplasmas with trypsin prior to the inoculation of monolayers resulted in a marked reduction in adherence. Treatment of the mycoplasmas with hyperimmune swine serum against M hyopneumoniae or normal swine serum resulted in 80 to 90% reduction of adherence; however, no inhibition occurred when mycoplasmas were treated with purified IgG from the hyperimmune serum.

  12. Scaling up a treatment to simultaneously remove persistent organic pollutants and heavy metals from contaminated soils.

    PubMed

    Rivero-Huguet, Mario; Marshall, William D

    2011-04-01

    Soil washing is a treatment process that can be used to remediate both organic and inorganic pollutants from contaminated soils, sludges, and sediments. A soil washing procedure was evaluated utilizing about 100g samples of soil that had been field-contaminated with arsenic, chromium, copper, pentachlorophenol (PCP), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The highest level of mobilization/detoxification was achieved in three soil washes with a mixture of 0.1M [S,S]-ethyelnediaminedisuccinate ([S,S]-EDDS) and 2% Brij 98 at pH 9 with 20 min of ultrasonication treatment at room temperature. This combination mobilized 70% of arsenic, 75% of chromium, 80% of copper, 90% of PCP, and 79% of PCDDs and PCDFs, so that the decontaminated soil met the maximum acceptable concentrations of the generic C-level criteria regulated by the Ministère du Développement Durable, de l'Environnement et des Parcs for the Province of Québec, Canada. The organic pollutants were back-extracted from the aqueous suspension with hexane. Heavy metals were virtually completely precipitated from the aqueous washing suspension with Mg(0) particles at room temperature. The PCP was detoxified by catalytic hydrodechlorination with a stream of 5% (v/v) H(2)-supercritical CO(2) that transported the organosoluble fraction through a reaction chamber containing 2% Pd/γ-Al(2)O(3). In toto, this soil washing procedure demonstrates that persistent organic pollutants and selected heavy metals can be co-extracted efficiently from a field-contaminated soil with three successive washes with the same soil washing solution containing [S,S]-EDDS and a non-ionic surfactant (Brij 98) in admixture. An industrial-scale ex situ soil washing procedure with a combination of a non-ionic surfactant and a complexing reagent seems to be a plausible remediation technique for this former wooden utility pole storage facility. PMID:21354593

  13. Intestinal absorption and biomagnification of organic contaminants in fish, wildlife, and humans.

    PubMed

    Kelly, Barry C; Gobas, Frank A P C; McLachlan, Michael S

    2004-10-01

    Methods for the regulatory assessment of the bioaccumulation potential of organic chemicals are founded on empirical measurements and mechanistic models of dietary absorption and biomagnification. This study includes a review of the current state of knowledge regarding mechanisms and models of intestinal absorption and biomagnification of organic chemicals in organisms of aquatic and terrestrial food chains and also includes a discussion of the implications of these models for assessing the bioaccumulation potential of organic chemicals. Four mechanistic models, including biomass conversion, digestion or gastrointestinal magnification, micelle-mediated diffusion, and fat-flush diffusion, are evaluated. The models contain many similarities and represent an evolution in understanding of chemical bioaccumulation processes. An important difference between the biomagnification models is whether intestinal absorption of an ingested contaminant occurs solely via passive molecular diffusion through serial resistances or via facilitated diffusion that incorporates an additional advective transport mechanism in parallel (i.e., molecular ferrying within gastrointestinal micelles). This difference has an effect on the selection of physicochemical properties that best anticipate the bioaccumulative potential of commercial chemicals in aquatic and terrestrial food chains. Current regulatory initiatives utilizing Kow threshold criteria to assess chemical bioaccumulation potential are shown to be unable to identify certain bioaccumulative substances in air-breathing animals. We urge further research on dietary absorption and biomagnification of organic chemicals to develop better models for assessing the bioaccumulative nature of organic chemicals. PMID:15511095

  14. An evaluation of alternative cleaning methods for removing an organic contaminant from a stainless steel part

    SciTech Connect

    Boyd, J.L.

    1996-08-01

    As of December 1995, the manufacture of Freon, along with many other chlorofluorocarbons (CFCs), was prohibited by the Clean Air Act of 1990 (CAA). The ban of CFC solvents has forced manufacturers across the country to search for alternative metal cleaning techniques. The objective of this study was to develop a thorough, scientific based approach for resolving one specific manufacturer`s problem of removing organic contamination from a stainless steel part. This objective was accomplished with an approach that involved: (1) defining the problem, (2) identifying the process constraints, (3) researching alternate cleaning methods, (4) researching applicable government regulations, (5) performing a scientific evaluation and (6) drawing conclusions.

  15. Occurrence of organic wastewater and other contaminants in cave streams in northeastern Oklahoma and northwestern Arkansas

    USGS Publications Warehouse

    Bidwell, Joseph R.; Becker, C.; Hensley, S.; Stark, R.; Meyer, M.T.

    2010-01-01

    The prevalence of organic wastewater compounds in surface waters of the United States has been reported in a number of recent studies. In karstic areas, surface contaminants might be transported to groundwater and, ultimately, cave ecosystems, where they might impact resident biota. In this study, polar organic chemical integrative samplers (POCISs) and semipermeable membrane devices (SPMDs) were deployed in six caves and two surface-water sites located within the Ozark Plateau of northeastern Oklahoma and northwestern Arkansas in order to detect potential chemical contaminants in these systems. All caves sampled were known to contain populations of the threatened Ozark cavefish (Amblyopsis rosae). The surface-water site in Oklahoma was downstream from the outfall of a municipal wastewater treatment plant and a previous study indicated a hydrologic link between this stream and one of the caves. A total of 83 chemicals were detected in the POCIS and SPMD extracts from the surface-water and cave sites. Of these, 55 chemicals were detected in the caves. Regardless of the sampler used, more compounds were detected in the Oklahoma surface-water site than in the Arkansas site or the caves. The organic wastewater chemicals with the greatest mass measured in the sampler extracts included sterols (cholesterol and ??-sitosterol), plasticizers [diethylhexylphthalate and tris (2-butoxyethyl) phosphate], the herbicide bromacil, and the fragrance indole. Sampler extracts from most of the cave sites did not contain many wastewater contaminants, although extracts from samplers in the Oklahoma surfacewater site and the cave hydrologically linked to it had similar levels of diethylhexyphthalate and common detections of carbamazapine, sulfamethoxazole, benzophenone, N-diethyl-3-methylbenzamide (DEET), and octophenol monoethoxylate. Further evaluation of this system is warranted due to potential ongoing transport of wastewaterassociated chemicals into the cave. Halogenated organics

  16. Occurrence of organic wastewater and other contaminants in cave streams in northeastern Oklahoma and northwestern Arkansas.

    PubMed

    Bidwell, Joseph R; Becker, Carol; Hensley, Steve; Stark, Richard; Meyer, Michael T

    2010-02-01

    The prevalence of organic wastewater compounds in surface waters of the United States has been reported in a number of recent studies. In karstic areas, surface contaminants might be transported to groundwater and, ultimately, cave ecosystems, where they might impact resident biota. In this study, polar organic chemical integrative samplers (POCISs) and semipermeable membrane devices (SPMDs) were deployed in six caves and two surface-water sites located within the Ozark Plateau of northeastern Oklahoma and northwestern Arkansas in order to detect potential chemical contaminants in these systems. All caves sampled were known to contain populations of the threatened Ozark cavefish (Amblyopsis rosae). The surface-water site in Oklahoma was downstream from the outfall of a municipal wastewater treatment plant and a previous study indicated a hydrologic link between this stream and one of the caves. A total of 83 chemicals were detected in the POCIS and SPMD extracts from the surface-water and cave sites. Of these, 55 chemicals were detected in the caves. Regardless of the sampler used, more compounds were detected in the Oklahoma surface-water site than in the Arkansas site or the caves. The organic wastewater chemicals with the greatest mass measured in the sampler extracts included sterols (cholesterol and beta-sitosterol), plasticizers [diethylhexylphthalate and tris(2-butoxyethyl) phosphate], the herbicide bromacil, and the fragrance indole. Sampler extracts from most of the cave sites did not contain many wastewater contaminants, although extracts from samplers in the Oklahoma surface-water site and the cave hydrologically linked to it had similar levels of diethylhexyphthalate and common detections of carbamazapine, sulfamethoxazole, benzophenone, N-diethyl-3-methylbenzamide (DEET), and octophenol monoethoxylate. Further evaluation of this system is warranted due to potential ongoing transport of wastewater-associated chemicals into the cave. Halogenated organics

  17. Occurrence of organic wastewater and other contaminants in cave streams in northeastern Oklahoma and northwestern Arkansas.

    PubMed

    Bidwell, Joseph R; Becker, Carol; Hensley, Steve; Stark, Richard; Meyer, Michael T

    2010-02-01

    The prevalence of organic wastewater compounds in surface waters of the United States has been reported in a number of recent studies. In karstic areas, surface contaminants might be transported to groundwater and, ultimately, cave ecosystems, where they might impact resident biota. In this study, polar organic chemical integrative samplers (POCISs) and semipermeable membrane devices (SPMDs) were deployed in six caves and two surface-water sites located within the Ozark Plateau of northeastern Oklahoma and northwestern Arkansas in order to detect potential chemical contaminants in these systems. All caves sampled were known to contain populations of the threatened Ozark cavefish (Amblyopsis rosae). The surface-water site in Oklahoma was downstream from the outfall of a municipal wastewater treatment plant and a previous study indicated a hydrologic link between this stream and one of the caves. A total of 83 chemicals were detected in the POCIS and SPMD extracts from the surface-water and cave sites. Of these, 55 chemicals were detected in the caves. Regardless of the sampler used, more compounds were detected in the Oklahoma surface-water site than in the Arkansas site or the caves. The organic wastewater chemicals with the greatest mass measured in the sampler extracts included sterols (cholesterol and beta-sitosterol), plasticizers [diethylhexylphthalate and tris(2-butoxyethyl) phosphate], the herbicide bromacil, and the fragrance indole. Sampler extracts from most of the cave sites did not contain many wastewater contaminants, although extracts from samplers in the Oklahoma surface-water site and the cave hydrologically linked to it had similar levels of diethylhexyphthalate and common detections of carbamazapine, sulfamethoxazole, benzophenone, N-diethyl-3-methylbenzamide (DEET), and octophenol monoethoxylate. Further evaluation of this system is warranted due to potential ongoing transport of wastewater-associated chemicals into the cave. Halogenated organics

  18. The role of clay in enhancing attenuation of trace organic contaminants during managed aquifer recharge

    NASA Astrophysics Data System (ADS)

    Regnery, J.; Strasser, A.; Hake, E.; Wing, A.; Drewes, J. E.

    2013-12-01

    For more hydrophobic trace organic contaminants present in surface water or reclaimed water applied for managed aquifer recharge (MAR), sorption onto organic matter can play a major role in attenuation in subsurface systems as the retardation allows more time for biotransformation. In case of low organic matter, other sorptive processes such as interactions with mineral surfaces gain importance. Especially for positively charged molecules, sorption onto clay materials by cation exchange will play a significant role. However, if the cation exchange capacity is limited or sorption of trace organic contaminants to clay materials is reversible due to changes in geochemical conditions (i.e., pH, ion strength), this might not provide a sustainable removal pathway. The objective of this study is to investigate how sorption to clay can enhance the removal of trace organic contaminants during MAR with the goal of evaluating the feasibility (i.e., infiltration capacity) and benefit (i.e., retardation of recalcitrant compounds) of introducing clay materials as reactive barriers in MAR systems. Laboratory-scale soil column experiments and batch sorption experiments using well characterized soil mixtures with different clay percentages under abiotic conditions and spiked at environmentally relevant concentration levels were conducted to derive soil water distribution coefficients for a suite of 15 trace organic chemicals (i.e., pharmaceutical residues, personal care products, household chemicals) and to quantify their sorption/desorption potential. All clay materials used in this study were characterized by X-ray diffraction to obtain information regarding their sorption processes. Furthermore, results were compared with geochemical field data from a full-scale MAR site in Colorado where significant amounts of clay in the subsurface were present. Preliminary results indicated that certain clay materials bear a great potential to retain moderately hydrophobic compounds such as

  19. Development of HUMASORB{trademark}, a lignite derived humic acid for removal of metals and organic contaminants from groundwater

    SciTech Connect

    Sanjay, H.G.; Srivastave, K.C.; Walia, D.S.

    1995-10-01

    Heavy metal and organic contamination of surface and groundwater systems is a major environmental concern. The contamination is primarily due to improperly disposed industrial wastes. The presence of toxic heavy metal ions, volatile organic compounds (VOCs) and pesticides in water is of great concern and could affect the safety of drinking water. Decontamination of surface and groundwater can be achieved using a broad spectrum of treatment options such as precipitation, ion-exchange, microbial digestion, membrane separation, activated carbon adsorption, etc. The state of the art technologies for treatment of contaminated water however, can in one pass remediate only one class of contaminants, i.e., either VOCs (activated carbon) or heavy metals (ion exchange). This would require the use of at a minimum, two different stepwise processes to remediate a site. The groundwater contamination at different Department of Energy (DOE) sites (e.g., Hanford) is due to the presence of both VOCs and heavy metals. The two-step approach increases the cost of remediation. To overcome the sequential treatment of contaminated streams to remove both organics and metals, a novel material having properties to remove both classes of contaminants in one step is being developed as part of this project.The objective of this project is to develop a lignite-derived adsorbent, Humasorb{sup TM} to remove heavy metals and organics from ground water and surface water streams.

  20. ToF-SIMS Applications in Microelectronics: Quantification of Organic Surface Contamination

    NASA Astrophysics Data System (ADS)

    Trouiller, C.; Signamarcheix, T.; Juhel, M.; Petitdidier, S.; Fontaine, H.; Veillerot, M.; Kwakman, L. F. Tz.; Wyon, C.

    2005-09-01

    An overview of our main Time-Of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) applications is first given that highlights the strengths but also reveals some development needs for this technique especially where it comes to contaminants quantification. In this work, as a step towards better quantified data, we have elaborated a method to quantify Airborne Molecular Contamination (AMC) on Silicon. For this a protocol using liquid nitrogen sample cooling was set up to reduce the desorption of the most volatile species under the Ultra High Vacuum (UHV) of the ToF-SIMS analysis chamber and thus to enable a more stable, reliable and representative measurement. Using this protocol for the ToF-SIMS analysis and a careful analytical sequence, good correlation between Wafer Thermal Desorption Gas Chromatography Mass Spectroscopy (W-TDGCMS) and ToF-SIMS results on wafers exposed for varying time under the clean-room air flow containing 2,2,4-trimethyl 1,3-pentanediol diisobutyrate (TXIB) and Phthalates — two main organic clean-room contaminants — is obtained. Relative Sensitivity Factors (RSF) are deduced. With the used measurement setups, the ToF-SIMS low detection limits (DL) lie around 1E11 - 1E12 atoms Carbon/cm2 (atC/cm2) depending on species and are comparable to that of W-TDGCMS at 1E11 atC/cm2.

  1. Occurrence, bioavailability and toxic effects of trace metals and organic contaminants in mangrove ecosystems: a review.

    PubMed

    Bayen, Stéphane

    2012-11-01

    Although their ecological and socioeconomic importance has received recent attention, mangrove ecosystems are one of the most threatened tropical environments. Besides direct clearance, hydrological alterations, climatic changes or insect infestations, chemical pollution could be a significant contributor of mangrove degradation. The present paper reviews the current knowledge on the occurrence, bioavailability and toxic effects of trace contaminants in mangrove ecosystems. The literature confirmed that trace metals, Polycyclic Aromatic Hydrocarbons (PAHs), Persistent Organic Pollutants (POPs), Pharmaceuticals and Personal Care Products (PPCPs) and Endocrine Disrupters Compounds (EDCs) have been detected in various mangrove compartments (water, sediments and biota). In some cases, these chemicals have associated toxic effects on mangrove ecosystem species, with potential impact on populations and biodiversity in the field. However, nearly all studies about the bioavailability and toxic effects of contaminants in mangrove ecosystems focus on selected trace metals, PAHs or some "conventional" POPs, and virtually no data exist for other contaminant groups. The specificities of mangrove ecosystems (e.g. biology, physico-chemistry and hydrology) support the need for specific ecotoxicological tools. This review highlights the major data and methodological gaps which should be addressed to refine the risk assessment of trace pollutants in mangrove ecosystems. PMID:22885665

  2. Time scales of organic contaminant dissolution from complex source zones: coal tar pools vs. blobs

    NASA Astrophysics Data System (ADS)

    Eberhardt, Christina; Grathwohl, Peter

    2002-11-01

    Groundwater contamination due to complex organic mixtures such as coal tar, creosote and fuels is a widespread problem in industrialized regions. Although most compounds in these mixtures are biodegradable, the contaminant sources are very persistent for many decades after the contamination occurred (e.g., more than 100 years ago at gasworks sites). This limited bioavailability is due to slow dissolution processes. This study presents results from a large scale tank experiment (8 m long) on the long-term (354 days) dissolution kinetics of BTEX and PAHs from a 2.5 m long coal tar pool and 0.5 m long (smear) zone containing coal tar blobs distributed in a coarse sand. The results indicate (1) that Raoult's law holds for estimation of the saturation aqueous concentrations of the coal tar constituents, (2) that for the dissolution of smear zones longer than approximately 0.1 m and with more than 3-5% residual saturation, the local equilibrium assumption is valid and (3) that although very small (<0.1 mm), the transverse vertical dispersivity dominates the pool dissolution processes. Typical time scales for removal of the pollutants from the blob zone and the pool are in the order of a few weeks to more than 10,000 years, respectively.

  3. Time scales of organic contaminant dissolution from complex source zones: coal tar pools vs. blobs.

    PubMed

    Eberhardt, Christina; Grathwohl, Peter

    2002-11-01

    Groundwater contamination due to complex organic mixtures such as coal tar, creosote and fuels is a widespread problem in industrialized regions. Although most compounds in these mixtures are biodegradable, the contaminant sources are very persistent for many decades after the contamination occurred (e.g., more than 100 years ago at gasworks sites). This limited bioavailability is due to slow dissolution processes. This study presents results from a large scale tank experiment (8 m long) on the long-term (354 days) dissolution kinetics of BTEX and PAHs from a 2.5 m long coal tar pool and 0.5 m long (smear) zone containing coal tar blobs distributed in a coarse sand. The results inidicate (1) that Raoult's law holds for estimation of the saturation aqueous concentrations of the coal tar constituents, (2) that for the dissolution of smear zones longer than approximately 0.1 m and with more than 3-5% residual saturation, the local equilibrium assumption is valid and (3) that although very small (< 0.1 mm), the transverse vertical dispersivity dominates the pool dissolution processes. Typical time scales for removal of the pollutants from the blob zone and the pool are in the order of a few weeks to more than 10,000 years, respectively. PMID:12683639

  4. Time scales of organic contaminant dissolution from complex source zones: coal tar pools vs. blobs.

    PubMed

    Eberhardt, Christina; Grathwohl, Peter

    2002-11-01

    Groundwater contamination due to complex organic mixtures such as coal tar, creosote and fuels is a widespread problem in industrialized regions. Although most compounds in these mixtures are biodegradable, the contaminant sources are very persistent for many decades after the contamination occurred (e.g., more than 100 years ago at gasworks sites). This limited bioavailability is due to slow dissolution processes. This study presents results from a large scale tank experiment (8 m long) on the long-term (354 days) dissolution kinetics of BTEX and PAHs from a 2.5 m long coal tar pool and 0.5 m long (smear) zone containing coal tar blobs distributed in a coarse sand. The results inidicate (1) that Raoult's law holds for estimation of the saturation aqueous concentrations of the coal tar constituents, (2) that for the dissolution of smear zones longer than approximately 0.1 m and with more than 3-5% residual saturation, the local equilibrium assumption is valid and (3) that although very small (< 0.1 mm), the transverse vertical dispersivity dominates the pool dissolution processes. Typical time scales for removal of the pollutants from the blob zone and the pool are in the order of a few weeks to more than 10,000 years, respectively.

  5. Permeable Adsorptive Barrier (PAB) for the remediation of groundwater simultaneously contaminated by some chlorinated organic compounds.

    PubMed

    Erto, A; Bortone, I; Di Nardo, A; Di Natale, M; Musmarra, D

    2014-07-01

    In this paper, a Permeable Reactive Barrier (PRB) made with activated carbon, namely a Permeable Adsorptive Barrier (PAB), is put forward as an effective technique for the remediation of aquifers simultaneously contaminated by some chlorinated organic compounds. A design procedure, based on a computer code and including different routines, is presented as a tool to accurately describe mass transport within the aquifer and adsorption/desorption phenomena occurring inside the barrier. The remediation of a contaminated aquifer near a solid waste landfill in the district of Napoli (Italy), where Tetrachloroethylene (PCE) and Trichloroethylene (TCE) are simultaneously present, is considered as a case study. A complete hydrological and geotechnical site characterization, as well as a number of dedicated adsorption laboratory tests for the determination of activated carbon PCE/TCE adsorption capacity in binary systems, are carried out to support the barrier design. By means of a series of numerical simulations it is possible to determine the optimal barrier location, orientation and dimensions. PABs appear to be an effective remediation tool for the in-situ treatment of an aquifer contaminated by PCE and TCE simultaneously, as the concentration of both compounds flowing out of the barrier is everywhere lower than the regulatory limits on groundwater quality.

  6. Development of adsorbent for the simultaneous removal of organic and inorganic contaminants from aqueous solution.

    PubMed

    Choi, J W; Chung, S G; Hong, S W; Kim, D J; Lee, S H

    2011-01-01

    In this study, a modified adsorbent, alginate complex beads, was prepared and applied to the removal of mixed contaminants from wastewater. The alginate complex beads were generated by the immobilization of powdered activated carbon and synthetic zeolites onto alginate gel beads, which were then dried at 110 °C for 20 h until the diameter had been reduced to 1 mm. This dry technique increased the hardness of the adsorbent to assure its durability and application. The adsorption onto the alginate complex beads of organic and inorganic compounds, as target contaminants, was investigated by performing both equilibrium and kinetic batch experiments. From the adsorption isotherms, according to the Langmuir equation, the alginate complex bead was capable of effectively removing benzene, toluene, zinc and cadmium. From kinetic batch experiments, the removal efficiencies of benzene, toluene, zinc and cadmium were found to be 66.5, 92.4, 74.1 and 76.7%, respectively, for initial solution concentrations of 100 mg L(-1). The results indicated that the adsorbent developed in this study has the potential to be a promising material for the removal of mixed pollutants from industrial wastewater or contaminated groundwater. PMID:22020474

  7. Critical body residues in the marine amphipod Ampelisca abdita: Sediment exposures with nonionic organic contaminants

    SciTech Connect

    Fay, A.A.; Brownawell, B.J.; Elskus, A.A.; McElroy, A.E.

    2000-04-01

    Body residues associated with acute toxicity were determined in the marine amphipod Ampelisca abdita exposed to spiked sediments. Nonylphenol and 2,2{prime},4,4{prime}-tetrachlorobiphenyl critical body residues (CBRs, body residue of contaminant at 50% mortality) were 1.1 {micro}mol/g wet tissue and 0.57 {micro}mol/g wet tissue, respectively, values near the low end of the CBR range expected for compounds acting via narcosis. The polycyclic aromatic hydrocarbons tested, benzo[a]pyrene (BaP) and benz[a]anthracene (BaA), were not acutely toxic at exposure concentrations of up to 43 and 1,280 {micro}g/g dry sediment for BaA and BaP respectively, and body burdens up to 1.2 {micro}mol/g wet tissue (for BaP). Neither polycyclic aromatic hydrocarbon (PAH) was significantly metabolized by A. abdita. The microextraction technique employed here allowed residue analysis of samples containing as few as three amphipods (0.33 mg dry wt). The CBR approach avoids confounding factors such as variations in bioavailability and uptake kinetics and could be employed to assess the relative contribution of specific contaminants or contaminant classes in mixtures to effects observed in toxicity tests with Ampelisca and other organisms.

  8. The plume fringe concept - Biodegradation of organic contaminants in subsurface ecosystems

    NASA Astrophysics Data System (ADS)

    Meckenstock, R. U.; Griebler, C.; Anneser, B.; Winderl, C.; Bauer, R.; Lüders, T.; Kellermann, C.; Selesi, D.

    2005-12-01

    The biodegradation of organic pollutants in groundwater systems may be limited by the depletion of essential nutrients or the low number of degraders. However, the main problem seems to be the insufficient mixing of e-donors and e-acceptors. Main degradation activities in contaminant plumes are therefore located at their fringes. In order to investigate the ecology of pollutant-degrading microbes, experiments are carried out (1) in 2D-aquifer model systems and (2) sediment cores were drilled at a former gasworks site and a novel high-resolution multilevel sampling well was installed. (1) To assess the importance of individual abiotic (e.g. mixing, toxicity, nutrients) and biotic (e.g. cell distribution and activity, redox tolerance) parameters for biodegradation under well controlled lab conditions, contaminant plumes are generated in 2D-model systems and subsequently inoculated with aerobic and/or anaerobic bacterial strains to investigate biodegradation in a spatially resolved manner. (2) To recognize limitations of biodegradation in a PAH-contaminated aquifer, sediment cores were taken and, at the same site, a high-resolution multilevel well was installed for frequent groundwater sampling with varying spatial resolution (from cm to m range). In both systems, degradation of contaminants is followed by vertically resolved concentration measurements, compound-specific stable isotope (D/H, 13C/12C) analysis and the identification of signature metabolites. Physical-chemical gradients are resolved by means of microsensors and geochemical sediment and water analysis. The spatial distribution of microbial biomass, individual groups of microbes and the presence of functional genes coding for potential degradation activities are investigated using molecular tools. First results of the work, which is embedded in two current projects, will be discussed.

  9. Groundwater contamination by organic bases derived from coal-tar wastes

    USGS Publications Warehouse

    Pereira, W.E.; Rostad, C.E.; Garbarino, J.R.; Hult, M.F.

    1983-01-01

    A fluid sample from a shallow aquifer contaminated by coal-tar wastes was analyzed for organic bases. The sample consisted of a mixture of aqueous and oily-tar phases. The phases were separated by centrifugation and filtration. Organic bases were isolated from each phase by pH adjustment and solvent extraction. Organic bases in the oily-tar phase were further purified by neutral-alumina, micro-column adsorption chromatography. Separation and identification of the organic bases in each phase were achieved by using capillary gas chromatography-mass spectrometry-computer (GC-MS-COM) and probe distillation-high resolution mass spectrometry (PD-HRMS) techniques. Organic bases present in the aqueous phase included primary aromatic amines (such as aniline, alkylated anilines, and naphthylamines) as well as azaarenes (such as alkylated pyridines, quinolines, acridine, and benzoquinolines). The oily-tar phase contained acridine, benzacridines, dibenzacridines, and numerous other azaarenes, the elemental compositions of which were determined by PD-HRMS. Azaarenes in the oily-tar phase, varying in size from 6 to 12 rings, are reported for the first time. The origin and environmental significance of these compounds are discussed. ?? 1983.

  10. Ground-water contamination by organic bases derived from coal-tar wastes

    USGS Publications Warehouse

    Pereira, Wilfred E.; Rostad, Colleen E.; Garbarino, John R.; Hult, Marc F.

    1983-01-01

    A fluid sample from a shallow aquifer contaminated by coal-tar wastes was analyzed for organic bases. The sample consisted of a mixture of aqueous and oily-tar phases. The phases were separated by centrifugation and filtration. Organic bases were isolated from each phase by pH adjustment and solvent extraction. Organic bases in the oily-tar phase were further purified by neutral-alumina, micro-column adsorption chromatography. Separation and identification of the organic bases in each phase were achieved by using capillary gas chromatography-mass spectrometry-computer (GC-MS-COM) and probe distillation-high resolution mass spectrometry (PD-HRMS) techniques. Organic bases present in the aqueous phase included primary aromatic amines (such as aniline, alkylated anilines, and naphthylamines) as well as azaarenes (such as alkylated pyridines, quinolines, acridine, and benzoquinolines). The oily-tar phase contained acridine, benzacridines, dibenzacridines, and numerous other azaarenes, the elemental compositions of which were determined by PD-HRMS. Azaarenes in the oily-tar phase, varying in size from 6 to 12 rings, are reported for the first time. The origin and environmental significance of these compounds are discussed.

  11. Properties governing the transport of trace organic contaminants through ion-exchange membranes.

    PubMed

    Vanoppen, Marjolein; Bakelants, Annelise F A M; Gaublomme, Dorien; Schoutteten, Klaas V K M; Vanden Bussche, Julie; Vanhaecke, Lynn; Verliefde, Arne R D

    2015-01-01

    Ion exchange membranes could provide a solution to the selective separation of organic and inorganic components in industrial wastewater. The phenomena governing the transport of organics through the IEM however, are not yet fully understood. Therefore, the transport of trace organic contaminants (TOrCs) as a model for a wide variety of organic compounds was studied under different conditions. It was found that in the absence of salt and external potential, the chemical equilibrium is the main driver for TOrC-transport, resulting in the transport of mainly charged TOrCs. When salt is present, the transport of TOrCs is hampered in favor of the NaCl transport, which shows a preferential interaction with the membranes due to its small size, high mobility and concentration. It is hypothesized that electrostatic interactions and electron donor/acceptor interactions are the main drivers for TOrC transport and that transport is mainly diffusion driven. This was confirmed in the experiments with different current densities, where the external potential seemed to have only a minor influence on the transport of TOrCs. It is only when the salt becomes nearly completely depleted that the TOrCs are transported as charge carriers. This shows that it is very difficult to get preferential transport of organic compounds due to the diffusive nature of their transport.

  12. Prevalence of organic and inorganic contaminants within a rapidly developing catchment

    NASA Astrophysics Data System (ADS)

    Njumbe, E. S.; Curtis, C. D.; Cooke, D. A.; Polya, D. A.; Wogelius, R. A.; Hughes, C.

    2003-04-01

    Industrialization rates in many developing countries typically outpace investment in water supply, sewage treatment and other waste water facilities. This is futher compounded by the absence of stringent land-use and waste disposal policies. The consequence of this has been contamination of land, surface water, and groundwater in such areas. Efforts to control and remediate these types of systems will rely on a thorough understanding of contaminant levels and mobility. Reliable data, however, is usually not available. Therefore this study was designed to acquire baseline data from a representative developing urban area in tropical west Africa. 43 water and 20 sediment/soil samples from streams, hand-dug wells, springs and deep boreholes within the city and surrounding areas of Douala in Cameroon were characterised. Analyses were aimed at obtaining information on the type and quantity of organic and inorganic contaminants present, and linking them to specific point and non-point sources. Results from gas chromatography (GC/FID) and gas chromatography/mass spectrometry analyses of total organic extracts (TOE) of water samples have revealed the presence of a wide range of organic compounds including phenols, polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), phthalates, acids and aliphatic derivatives. Concentrations as high as 500 ng ml-1 were detected. These high levels of non-polar compounds measured in drinking water represent a clear health problem. Heavy metal concentrations in bulk alluvial sands and loamy soil have been determined by microwave assisted nitric acid digestion. Concentration ranges (in ppm of dry weight) for the important metals were: Cr, 3.2-84.2 ; Ni, 0.2-57.4 ; Zn, 2.1-92 ; Pb, 0.3-33 ; As, 0.081-9.4 ; Cu, 0.61-17.4 ; and Cd, 0-3.1. Point sources have been identified for several of the organic and inorganic compounds and this spatial information will be integrated with the chemical data to present an overview of

  13. Emerging organic contaminants in groundwater: A review of sources, fate and occurrence.

    PubMed

    Lapworth, D J; Baran, N; Stuart, M E; Ward, R S

    2012-04-01

    Emerging organic contaminants (EOCs) detected in groundwater may have adverse effects on human health and aquatic ecosystems. This paper reviews the existing occurrence data in groundwater for a range of EOCs including pharmaceutical, personal care, 'life-style' and selected industrial compounds. The main sources and pathways for organic EOCs in groundwater are reviewed, with occurrence data for EOCs in groundwater included from both targeted studies and broad reconnaissance surveys. Nanogram-microgram per litre concentrations are present in groundwater for a large range of EOCs as well as metabolites and transformation products and under certain conditions may pose a threat to freshwater bodies for decades due to relatively long groundwater residence times. In the coming decades, more of these EOCs are likely to have drinking water standards, environmental quality standards and/or groundwater threshold values defined, and therefore a better understanding of the spatial and temporal variation remains a priority. PMID:22306910

  14. Evaluating non-incinerative treatment of organically contaminated low level mixed waste

    SciTech Connect

    Shuck, D.L.; Skriba, M.C.; Wade, J.F.

    1993-03-01

    This investigation examines the feasibility of using non-incinerator technologies effectively to treat organically contaminated mixed waste. If such a system is feasible now, it would be easier to license because it would avoid the stigma that incineration has in the publics` perception. As other DOE facilities face similar problems, this evaluation is expected to be of interest to both DOE and the attendees of WM`93. This investigation considered treatment to land disposal restriction (LDR) standards of 21 different low level mixed (LLM) waste streams covered by the Rocky Flats Federal Facilities Compliance Agreement (FFCA) agreement with the Environmental Protection Agency (EPA). Typically the hazardous components consists of organic solvent wastes and the radioactive component consists of uranic/transuranic wastes. Limited amounts of cyanide and lead wastes are also involved. The primary objective of this investigation was to identify the minimum number of non-thermal unit processes needed to effectively treat this collection of mixed waste streams.

  15. Evaluating non-incinerative treatment of organically contaminated low level mixed waste

    SciTech Connect

    Shuck, D.L. . Denver Environmental Services); Skriba, M.C. ); Wade, J.F. )

    1993-01-01

    This investigation examines the feasibility of using non-incinerator technologies effectively to treat organically contaminated mixed waste. If such a system is feasible now, it would be easier to license because it would avoid the stigma that incineration has in the publics' perception. As other DOE facilities face similar problems, this evaluation is expected to be of interest to both DOE and the attendees of WM'93. This investigation considered treatment to land disposal restriction (LDR) standards of 21 different low level mixed (LLM) waste streams covered by the Rocky Flats Federal Facilities Compliance Agreement (FFCA) agreement with the Environmental Protection Agency (EPA). Typically the hazardous components consists of organic solvent wastes and the radioactive component consists of uranic/transuranic wastes. Limited amounts of cyanide and lead wastes are also involved. The primary objective of this investigation was to identify the minimum number of non-thermal unit processes needed to effectively treat this collection of mixed waste streams.

  16. Emerging organic contaminants in groundwater: A review of sources, fate and occurrence.

    PubMed

    Lapworth, D J; Baran, N; Stuart, M E; Ward, R S

    2012-04-01

    Emerging organic contaminants (EOCs) detected in groundwater may have adverse effects on human health and aquatic ecosystems. This paper reviews the existing occurrence data in groundwater for a range of EOCs including pharmaceutical, personal care, 'life-style' and selected industrial compounds. The main sources and pathways for organic EOCs in groundwater are reviewed, with occurrence data for EOCs in groundwater included from both targeted studies and broad reconnaissance surveys. Nanogram-microgram per litre concentrations are present in groundwater for a large range of EOCs as well as metabolites and transformation products and under certain conditions may pose a threat to freshwater bodies for decades due to relatively long groundwater residence times. In the coming decades, more of these EOCs are likely to have drinking water standards, environmental quality standards and/or groundwater threshold values defined, and therefore a better understanding of the spatial and temporal variation remains a priority.

  17. An immunogenic Salmonella ghost confers protection against internal organ colonization and egg contamination.

    PubMed

    Jawale, Chetan V; Lee, John Hwa

    2014-11-15

    The tightly regulated expression of the PhiX174 lysis gene E from a multi-copy plasmid led to the stable production of an Salmonella Enteritidis bacterial ghost. The present study was conducted to evaluate induction of the humoral and cell-mediated immune responses induced after single or double intramuscular immunization with the S. Enteritidis ghost and to assess its protective effect on colonization of the intestinal tract, visceral and reproductive organs, internal egg contamination, and egg production of laying chickens. A total of 60 chickens were equally divided into three groups (n=20); group A (non-immunized control), group B (immunized at 8 and 16 weeks of age) and group C (immunized at 16th week of age). Chickens from both immunized groups B and C demonstrated significant increases in plasma IgG, intestinal secretory IgA levels, and antigen-specific lymphocyte proliferative responses. The population of CD3+CD4+ positive T cells in the immunized chickens was also significantly increased after immunization and virulent challenge. In addition, the immunized groups B and C showed significantly higher egg production and a lower percentage of S. Enteritidis contaminated eggs after challenge compared to those of group A. A comparison of challenge strain isolation from the immunized-challenged and non-immunized-challenged layer hens showed that the double immunization group induced excellent protection against intestinal, liver, splenic, and ovarian Salmonella colonization; however, the single immunized chickens showed lower counts only in the splenic and ovarian organs. Overall, the data give compelling evidence that vaccination with the S. Enteritidis ghost induced robust protective immunity against experimental avian salmonellosis and may contribute to the reduce incidence of egg contamination.

  18. Biomarkers of organic contamination in the South American fish Poecilia vivipara and Jenynsia multidentata.

    PubMed

    Stacke Ferreira, Roger; Monserrat, José Maria; Ribas Ferreira, Josencler Luís; Kalb, Ana Cristina; Stegeman, John; Dias Bainy, Afonso Celso; Zanette, Juliano

    2012-01-01

    South American cyprinodontiform fish are potential candidates to be used as model biomarker species of exposure in environmental toxicology. The aim of this study was to identify molecular and biochemical biomarkers of pollution using Poecilia vivipara (Poecilidae) and Jenynsia multidentata (Anablepidae). Partial nucleotide sequences for cytochrome P-450 1A (CYP1A), a classical biomarker of exposure to organic contaminants in fish, were identified in P. vivipara and J. multidentata (approximately 650 nucleotides) using degenerated primers and polymerase chain reaction (PCR). These sequences shared approximately 90% identity in the predicted amino acid sequence with the corresponding CYP1A region of Fundulus heteroclitus. Real-time quantitative PCR (RT-qPCR) analysis confirmed that CYP1A transcription was markedly induced in the liver and gills of J. multidentata (approximately185-fold and 20-fold, respectively) and P. vivipara (122-fold and 739-fold, respectively) 24 h after exposure to 1 μM synthetic CYP1A inducer β-naphthoflavone (BNF). At 24 h after injection with 1 μg/g environmental carcinogenic contaminant benzo[a]pyrene (BaP), a decreased total antioxidant capacity against peroxyl radicals was observed both in liver of J. multidentata and gills of P. vivipara. BaP injection in both fish did not produce changes in lipid peroxide (thiobarbituric acid-reactive substances, TBARS) levels, suggesting an absence of an oxidative stress condition. The newly identified CYP1A may thus serve as general biomarker of exposure to organic contaminant in future studies using P. vivipara and J. multidentata. Data also indicate the importance of species-specific differences in biomarker responses in these South American cyprinodontiform fish, suggesting distinct resistance/susceptibility properties to polycyclic aromatic hydrocarbons. PMID:22852852

  19. Organic contamination of highly oriented pyrolytic graphite as studied by scanning electrochemical microscopy.

    PubMed

    Nioradze, Nikoloz; Chen, Ran; Kurapati, Niraja; Khvataeva-Domanov, Anastasia; Mabic, Stéphane; Amemiya, Shigeru

    2015-05-01

    Highly oriented pyrolytic graphite (HOPG) is an important electrode material as a structural model of graphitic nanocarbons such as graphene and carbon nanotubes. Here, we apply scanning electrochemical microscopy (SECM) to demonstrate quantitatively that the electroactivity of the HOPG basal surface can be significantly lowered by the adsorption of adventitious organic impurities from both ultrapure water and ambient air. An SECM approach curve of (ferrocenylmethyl)trimethylammonium (FcTMA(+)) shows the higher electrochemical reactivity of the HOPG surface as the aqueous concentration of organic impurities, i.e., total organic carbon (TOC), is decreased from ∼20 to ∼1 ppb. SECM-based nanogap voltammetry in ∼1 ppb-TOC water yields unprecedentedly high standard electron-transfer rate constants, k(0), of ≥17 and ≥13 cm/s for the oxidation and reduction of the FcTMA(2+/+) couple, respectively, at the respective tip-HOPG distances of 36 and 45 nm. Anomalously, k(0) values and nanogap widths are different between the oxidation and reduction of the same redox couple at the same tip position, which is ascribed to the presence of an airborne contaminant layer on the HOPG surface in the noncontaminating water. This hydrophobic layer is more permeable to FcTMA(+) with less charge than its oxidized form so that the oxidation of FcTMA(+) at the HOPG surface results in the higher tip current and, subsequently, apparently narrower gap and higher k(0). Mechanistically, we propose that HOPG adsorbs organic impurities mainly from ambient air and then additionally from ∼20 ppb-TOC water. The latter tightens a monolayer of airborne contaminants to yield lower permeability.

  20. Hydrophobic organic contaminants in surficial sediments of Baltimore Harbor: Inventories and sources

    SciTech Connect

    Ashley, J.T.F.; Baker, J.E.

    1999-05-01

    The heavily urbanized and industrialized Baltimore Harbor/Patapsco River/Back River system is one of the most highly contaminated regions of the Chesapeake Bay. In June 1996, surficial sediments were collected at 80 sites throughout the subestuarine system, including historically undersampled creek sand embayments. The samples were analyzed for a suite of hydrophobic organic contaminants (HOCs) consisting of 32 polycyclic aromatic hydrocarbons (PAHs) and 113 polychlorinated biphenyl (PCB) congeners. Total PAH and total PCB concentrations ranged from 90 to 46,200 and 8 to 2,150 ng/g dry weight, respectively. There was enormous spatial variability in the concentrations of HOCs, which was not well correlated to grain size or organic carbon content, suggesting nonequilibrium partitioning and/or proximity to sources as important factors explaining the observed spatial variability. High concentrations of both classes of HOCs were localized around major urban stormwater runoff discharges. Elevated PAH concentrations were also centered around the Sparrow`s Point Industrial Complex, most likely a result of the pyrolysis of coal during the production of steel. All but 1 of the 80 sites exceeded the effects range-low (ERL) for total PCBs and, of those sites, 40% exceeded the effects range-medium (ERM), suggesting toxicity to marine benthic organisms would frequently occur. Using principal component analysis, differences in PAH signatures were discerned. Higher molecular weight PAHs were enriched in signatures from sediments close to suspected sources (i.e., urban stormwater runoff and steel production complexes) compared to those patterns observed at sites further from outfalls or runoff. Due to varying solubilities and affinities for organic matter of the individual PAHs, partitioning of the heavier weight PAHs may enrich settling particles with high molecular weight PAHs. Lower molecular weight PAHs, having lower affinity for particles, may travel from the source to a

  1. Assisted attenuation of a soil contaminated by diuron using hydroxypropyl-β-cyclodextrin and organic amendments.

    PubMed

    Rubio-Bellido, Marina; Madrid, Fernando; Morillo, Esmeralda; Villaverde, Jaime

    2015-01-01

    Diuron desorption and mineralisation were studied on an amended and artificially contaminated soil. The amendments used comprised two different composted organic residues i.e., sewage sludge (SS) mixed with pruning wastes, and urban solid residues (USR), and two different solutions (with inorganic salts as the micronutrients and hydroxypropyl-β-cyclodextrin (HPBCD)). After applying micronutrients to activate the soil flora, 15.5% mineralisation could be reached after 150 days, indicating that the soil has a potential capacity to mineralise the herbicide through biostimulation-assisted attenuation. Diuron mineralisation was also improved when HPBCD solutions were applied. Indeed, the extent of herbicide mineralisation reached 29.7% with this application. Moreover, both the lag phase and the half-life time (DT50) were reduced to 33 and 1,778 days, respectively, relative to the application of just micronutrients (i.e., 39 and 6297 days, respectively). Organic amendments were also applied (i.e., USR and SS) on the contaminated soil: it was found that the diuron mineralisation rate was improved as the amendment concentration increased. The joint application of all treatments investigated at the best conditions tested was conducted to obtain the best diuron mineralisation results. The micronutrient amendment plus 4% USR or SS amendment plus HPBCD solution (10-fold diuron initially spiked) caused an extent of diuron mineralisation 33.2 or 46.5%, respectively. PMID:25310830

  2. Organic contaminants and retinoids in Atlantic tomcod from two estuaries in the Gulf of St. Lawrence

    SciTech Connect

    Fairchild, W.L.; Arsenault, J.T.; Muir, D.C.G.; Brown, S.B.

    1994-12-31

    Atlantic tomcod (Microgadus tomcod) were collected in November 1993 from Miramichi Bay and Kouchibouguac Lagoon, on the Gulf of St. Lawrence coast of New Brunswick, Canada. The Miramichi has a long history of industrial and municipal activity, while Kouchibouguac Lagoon is within a National Park. Livers from male and female tomcod from each site were analyzed for organic contaminants. Sub-samples of the livers were analyzed for retinol (A{sub 1}), dehydroretinol (A{sub 2}), retinyl palmitate (A{sub 2}), and tocopherol (E). In addition, pooled livers from female smooth flounder (Pleuronectes putnami) from each site were analyzed for organic contaminants. Tomcod livers from the Miramichi had about 30x higher mean concentration of tri and tetrachloroveratrole (18 ng/g), and 6x higher concentration of pentachloroanisole (4.6 ng/g), than those from the Kouchibouguac. Total PCB congener concentration in liver was 1.5x higher in tomcod (116 ng/g), and 8x higher for smooth flounder (211 ng/g) from the Miramichi than the Kouchibouguac. Smooth flounder do not leave the estuaries, as tomcod do, during the summer. Little retinol or dehydroretinol was detected in tomcod livers from either site. Retinyl palmitate stores were lower in livers of fish from the Kouchibouguac, while tocopherol was detected but did not differ between sites.

  3. Genetic toxicity studies of organic chemicals found as contaminants in spacecraft cabin atmospheres

    NASA Technical Reports Server (NTRS)

    Torres, Joseph, Jr.

    1987-01-01

    Astronauts can be exposed during spaceflight to organic chemical contaminants in the spacecraft cabin atmosphere. Toxic exposures may cause lesions in the cellular DNA which are subsequently expressed as sister-chromatid exchanges (SCE). Analysis of SCE is a sensitive short term assay techinque to detect and quantitate exposures to DNA damaging (mutagenic) substances. The increase in SCE incidence over baseline (control) levels is generally proportional to the concentration of the mutagen and to the duration of exposure. The BHK-21 baby hamster kidney cell line was the in vitro test system used. Test organics were added to the culture media for 18 hrs, in concentrations ranging from one to 20 ppm. Acetaldehyde and carbon disulfide were chosen for this study since they have occurred as atmospheric contaminants in many of the STS flights, and have been reported to have toxic and mutagenic effects in various test systems. Glutaraldehyde was chosen because few data are available on the mutagenicity of this common fixative, which is carried on STS flights for use in biological experiments. Acetaldehyde was a very strong inducer of SCE at concentrations of 2 ppm and above. Glutaraldehyde and carbon disulfide failed to induce SCE.

  4. Long-Term Fate of Organic Micropollutants in Sewage-Contaminated Groundwater

    USGS Publications Warehouse

    Barber, L.B.; Schroeder, M.P.; LeBlanc, D.R.

    1988-01-01

    Disposal of secondary sewage effluent by rapid infiltration has produced a plume of contaminated groundwater over 3500 m long near Falmouth, MA. Approximately 50 volatile organic compounds were detected and identified in the plume, at concentrations ranging from 10 ng/L to 500 ??g/L, by closed-loop stripping and purge- and-trap in conjuction with gas chromatography-mass spectrometry. The dominant contaminants were di-, tri- and tetrachloroethene, o- and p-dichlorobenzene, C1 to C6 alkylbenzenes, 2,6-di-tert-butylbenzoquinone, and several isomers of p-nonylphenol. The chloroethenes and chlorobenzenes had the same general distribution as chloride and boron and appear to be transported with little retardation. Less soluble compounds, such as nonylphenol and di-tert-butylbenzoquinone, appear to be retarded during subsurface transport by sorption processes. Although biodegradation of labile organic compounds occurs near the infiltration beds, many trace compounds, including chlorinated benzenes, alkylbenzenes, and aliphatic hydrocarbons, have persisted for more than 30 years in the aquifer.

  5. Alternative tissue analysis method developed for organochlorine contaminants in aquatic organisms

    SciTech Connect

    Shan, T.H.; Hopple, J.A.; Foster, G.D. )

    1994-09-01

    The exposure of aquatic life to organochlorine contaminants has been investigated during the past two decades because of human and ecosystem health concerns related to the bioaccumulation of hazardous, lipophilic substances. The toxic effects of polychlorodibenzo-p-dioxines and polychlorinated biphenyls (PCBs) are well known, and recent evidence also suggests that low level exposure to lipophilic organochlorines may interfere with normal development during sensitive early life history stages. As the use of lipophilic organochlorines, such as DDT, in third world countries continues and with the purported global cycling and food chain accumulation of persistent organochlorines, the occurrence of these compounds in aquatic organisms is a critical global environmental issue. An understanding of the fate of organochlorines in the environmental clearly remains an extremely important subject related to water quality. The U.S. Geological Survey (USGS) has recently gained congressional approval in the United States to track nation wide trends in water quality through the establishment of the National Water Quality Assessment Program (NAWQA). Among the goals defined by NAWQA, aquatic organisms, including fish, shellfish, and plants, collected from major drainage basins will be analyzed for, along with other contaminants, polychlorinated biphenyls (PCBs), organochlorine insecticides, and chlorobenzenes. The purpose of this report is to present quality assurance data obtained from the development of a PCB, chlorobenzene, and organochlorine insecticide tissue analysis method in support of NAWQA and other large-scale water quality programs conducted through our laboratory. 12 refs., 1 fig., 2 tabs.

  6. Natural Magnetite: an efficient catalyst for the degradation of organic contaminant

    PubMed Central

    HE, Hongping; ZHONG, Yuanhong; LIANG, Xiaoliang; TAN, Wei; ZHU, Jianxi; Yan WANG, Christina

    2015-01-01

    Iron (hydr)oxides are ubiquitous earth materials that have high adsorption capacities for toxic elements and degradation ability towards organic contaminants. Many studies have investigated the reactivity of synthetic magnetite, while little is known about natural magnetite. Here, we first report the reactivity of natural magnetites with a variety of elemental impurities for catalyzing the decomposition of H2O2 to produce hydroxyl free radicals (•OH) and the consequent degradation of p-nitrophenol (p-NP). We observed that these natural magnetites show higher catalytic performance than that of the synthetic pure magnetite. The catalytic ability of natural magnetite with high phase purity depends on the surface site density while that for the magnetites with exsolutions relies on the mineralogical nature of the exsolved phases. The pleonaste exsolution can promote the generation of •OH and the consequent degradation of p-NP; the ilmenite exsolution has little effect on the decomposition of H2O2, but can increase the adsorption of p-NP on magnetite. Our results imply that natural magnetite is an efficient catalyst for the degradation of organic contaminants in nature. PMID:25958854

  7. Assisted attenuation of a soil contaminated by diuron using hydroxypropyl-β-cyclodextrin and organic amendments.

    PubMed

    Rubio-Bellido, Marina; Madrid, Fernando; Morillo, Esmeralda; Villaverde, Jaime

    2015-01-01

    Diuron desorption and mineralisation were studied on an amended and artificially contaminated soil. The amendments used comprised two different composted organic residues i.e., sewage sludge (SS) mixed with pruning wastes, and urban solid residues (USR), and two different solutions (with inorganic salts as the micronutrients and hydroxypropyl-β-cyclodextrin (HPBCD)). After applying micronutrients to activate the soil flora, 15.5% mineralisation could be reached after 150 days, indicating that the soil has a potential capacity to mineralise the herbicide through biostimulation-assisted attenuation. Diuron mineralisation was also improved when HPBCD solutions were applied. Indeed, the extent of herbicide mineralisation reached 29.7% with this application. Moreover, both the lag phase and the half-life time (DT50) were reduced to 33 and 1,778 days, respectively, relative to the application of just micronutrients (i.e., 39 and 6297 days, respectively). Organic amendments were also applied (i.e., USR and SS) on the contaminated soil: it was found that the diuron mineralisation rate was improved as the amendment concentration increased. The joint application of all treatments investigated at the best conditions tested was conducted to obtain the best diuron mineralisation results. The micronutrient amendment plus 4% USR or SS amendment plus HPBCD solution (10-fold diuron initially spiked) caused an extent of diuron mineralisation 33.2 or 46.5%, respectively.

  8. Natural Magnetite: an efficient catalyst for the degradation of organic contaminant.

    PubMed

    He, Hongping; Zhong, Yuanhong; Liang, Xiaoliang; Tan, Wei; Zhu, Jianxi; Wang, Christina Yan

    2015-01-01

    Iron (hydr)oxides are ubiquitous earth materials that have high adsorption capacities for toxic elements and degradation ability towards organic contaminants. Many studies have investigated the reactivity of synthetic magnetite, while little is known about natural magnetite. Here, we first report the reactivity of natural magnetites with a variety of elemental impurities for catalyzing the decomposition of H2O2 to produce hydroxyl free radicals (•OH) and the consequent degradation of p-nitrophenol (p-NP). We observed that these natural magnetites show higher catalytic performance than that of the synthetic pure magnetite. The catalytic ability of natural magnetite with high phase purity depends on the surface site density while that for the magnetites with exsolutions relies on the mineralogical nature of the exsolved phases. The pleonaste exsolution can promote the generation of •OH and the consequent degradation of p-NP; the ilmenite exsolution has little effect on the decomposition of H2O2, but can increase the adsorption of p-NP on magnetite. Our results imply that natural magnetite is an efficient catalyst for the degradation of organic contaminants in nature.

  9. Modeling of multiphase transport of multicomponent organic contaminants and heat in the subsurface: Numerical model formulation

    NASA Astrophysics Data System (ADS)

    Adenekan, A. E.; Patzek, T. W.; Pruess, K.

    1993-11-01

    A numerical compositional simulator (Multiphase Multicomponent Nonisothermal Organics Transport Simulator (M2NOTS)) has been developed for modeling transient, three-dimensional, nonisothermal, and multiphase transport of multicomponent organic contaminants in the subsurface. The governing equations include (1) advection of all three phases in response to pressure, capillary, and gravity forces; (2) interphase mass transfer that allows every component to partition into each phase present; (3) diffusion; and (4) transport of sensible and latent heat energy. Two other features distinguish M2NOTS from other simulators reported in the groundwater literature: (1) the simulator allows for any number of chemical components and every component is allowed to partition into all fluid phases present, and (2) each phase is allowed to completely disappear from, or appear in, any region of the domain during a simulation. These features are required to model realistic field problems involving transport of mixtures of nonaqueous phase liquid contaminants, and to quantify performance of existing and emerging remediation methods such as vacuum extraction and steam injection.

  10. Adherence of Staphylococcus epidermidis to intraocular lenses.

    PubMed Central

    Griffiths, P. G.; Elliot, T. S.; McTaggart, L.

    1989-01-01

    We have demonstrated, with an in vitro model, that Staphylococcus epidermidis is able to colonise intraocular lenses. Adherent organisms were quantitated by light microscopy, scanning electron microscopy, and viable counting. Bacterial adherence was associated with production of a polysaccharide glycocalyx. Organisms which were attached to the lenses were resistant to apparently bactericidal concentrations of antibiotics, as determined by conventional testing. We speculate on the role of colonisation in the pathogenesis of endophthalmitis. Images PMID:2751971

  11. Development of HUMASORB{trademark}, a lignite derived humic acid for removal of metals and organic contaminants from groundwater

    SciTech Connect

    Sanjay, H.G.; Srivastava, K.C.; Walia, D.S.

    1995-12-31

    Heavy metal and organic contamination of surface and groundwater systems is a major environmental concern. The contamination is primarily due to improperly disposed industrial wastes. The presence of toxic heavy metal ions, volatile organic compounds (VOCs) and pesticides in water is of great concern and could affect the safety of drinking water. Decontamination of surface and groundwater can be achieved using a broad spectrum of treatment options such as precipitation, ion-exchange, microbial digestion, membrane separation, activated carbon adsorption, etc. The state of the art technologies for treatment of contaminated water however, can in one pass remediate only one class of contaminants, i.e., either VOCs (activated carbon) or heavy metals (ion exchange). This would require the use of at a minimum, two different stepwise processes to remediate a site. The groundwater contamination at different Department of Energy (DOE) sites (e.g., Hanford) is due to the presence of both VOCs and heavy metals. The two-step approach increases the cost of remediation. To overcome the sequential treatment of contaminated streams to remove both organics and metals, a novel material having properties to remove both classes of contaminants in one step is being developed as part of this project.

  12. Application of compost for effective bioremediation of organic contaminants and pollutants in soil.

    PubMed

    Kästner, Matthias; Miltner, Anja

    2016-04-01

    Soils contaminated with hazardous chemicals worldwide are awaiting remediation activities; bioremediation is often considered as a cost-effective remediation approach. Potential bioapproaches are biostimulation, e.g. by addition of nutrients, fertiliser and organic substrates, and bioaugmentation by addition of compound-degrading microbes or of organic amendments containing active microorganisms, e.g. activated sludge or compost. In most contaminated soils, the abundance of the intrinsic metabolic potential is too low to be improved by biostimulation alone, since the physical and chemical conditions in these soils are not conducive to biodegradation. In the last few decades, compost or farmyard manure addition as well as composting with various organic supplements have been found to be very efficient for soil bioremediation. In the present minireview, we provide an overview of the composting and compost addition approaches as 'stimulants' of natural attenuation. Laboratory degradation experiments are often biased either by not considering the abiotic factors or by focusing solely on the elimination of the chemicals without taking the biotic factors and processes into account. Therefore, we first systemise the concepts of composting and compost addition, then summarise the relevant physical, chemical and biotic factors and mechanisms for improved contaminant degradation triggered by compost addition. These factors and mechanisms are of particular interest, since they are more relevant and easier to determine than the composition of the degrading community, which is also addressed in this review. Due to the mostly empirical knowledge and the nonstandardised biowaste or compost materials, the field use of these approaches is highly challenging, but also promising. Based on the huge metabolic diversity of microorganisms developing during the composting processes, a highly complex metabolic diversity is established as a 'metabolic memory' within developing and mature

  13. Influences of binding to dissolved organic matter on hydrophobic organic compounds in a multi-contaminant system: Coefficients, mechanisms and ecological risks.

    PubMed

    Li, Yi-Long; He, Wei; Liu, Wen-Xiu; Kong, Xiang-Zhen; Yang, Bin; Yang, Chen; Xu, Fu-Liu

    2015-11-01

    The complexation flocculation (CF) method was successfully employed to identify binding coefficients (Kdoc) of specific organic contaminants to dissolved organic matter (DOM, often indicated by dissolved organic carbon, DOC) in a multi-contaminant hydrophobic organic contaminant (HOC) system. Kdoc values were obtained for most of the evaluated 33 HOCs, indicating the feasibility and applicability of the CF method in a multi-contaminant system. Significant positive correlations were observed between binding coefficients and octanol-water partition coefficients (Kow) for organic halogen compounds, such as polybrominated diphenyl ethers (PBDEs) (R(2) = 0.95, p < 0.05) and organic chlorine pesticides (OCPs) (methoxychlor excluded, R(2) = 0.82, p < 0.05). The positive correlations identified between the lgKdoc and lgBCF (bioconcentration factor) for PBDEs and OCPs, as well as the negative correlation observed for polycyclic aromatic hydrocarbons (PAHs), indicated that different binding or partition mechanisms between PAHs and organic halogen compounds exist. These differences further result in discriminative competition partitions of HOCs between DOM and organisms. Assuming that only freely dissolved HOCs are bioconcentrative, the results of DOM-influenced bioconcentration factor (BCFDOM) and DOM-influenced lowest observed effect level (LOELDOM) indicate that the ecological risk of HOCs is decreased by DOM.

  14. Harvesting contaminants from liquid

    DOEpatents

    Simpson, John T.; Hunter, Scott R.

    2016-05-31

    Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a vessel for storing the contaminated fluid. The vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus allowing the contaminants to be harvested.

  15. Plant-microbe interactions as drivers of ecosystem functions relevant for the biodegradation of organic contaminants.

    PubMed

    Fester, Thomas; Giebler, Julia; Wick, Lukas Y; Schlosser, Dietmar; Kästner, Matthias

    2014-06-01

    The plant organism and associated microbial communities can be seen as a sunlight driven hotspot for the turnover of organic chemicals. In such environments the fate of a chemical will not only depend on its intrinsic structural stability toward (bio-)chemical reactions and its bioavailability but also on the functional effectiveness and stability of natural microbial communities as main drivers of natural attenuation of chemicals. Recent research demonstrates that interactions between plants and microorganisms are crucial for the biotransformation of organic chemicals, for various processes affecting the bioavailability of such compounds, and for the stability of the affected ecosystem. Practical bioremediation approaches, therefore, should encompass integrated measures targeting functional vegetation as well as functional microbial communities. Good examples for a successful practical approach are constructed wetlands, where an artificial, simplified ecosystem is used for the detoxification of organic contaminants. While such systems have considerable practical success, they are often treated as a black box and a sound mechanistic understanding of functional resilience and of the 'reactive power' of such plant-microbe ecosystems is poor. This situation has to change, if progress in the application of bioremediation is to be made.

  16. Transport of Organic Contaminants Mobilized from Coal through Sandstone Overlying a Geological Carbon Sequestration Reservoir

    SciTech Connect

    Zhong, Lirong; Cantrell, Kirk J.; Bacon, Diana H.; Shewell, Jesse L.

    2014-02-01

    Column experiments were conducted using a wetted sandstone rock installed in a tri-axial core holder to study the flow and transport of organic compounds mobilized by scCO2 under simulated geologic carbon storage (GCS) conditions. The sandstone rock was collected from a formation overlying a deep saline reservoir at a GCS demonstration site. Rock core effluent pressures were set at 0, 500, or 1000 psig and the core temperature was set at 20 or 50°C to simulate the transport to different subsurface depths. The concentrations of the organic compounds in the column effluent and their distribution within the sandstone core were monitored. Results indicate that the mobility though the core sample was much higher for BTEX compounds than for naphthalene. Retention of organic compounds from the vapor phase to the core appeared to be primarily controlled by partitioning from the vapor phase to the aqueous phase. Adsorption to the surfaces of the wetted sandstone was also significant for naphthalene. Reduced temperature and elevated pressure resulted in greater partitioning of the mobilized organic contaminants into the water phase.

  17. Identification of specific organic contaminants in different units of a chemical production site.

    PubMed

    Dsikowitzky, L; Botalova, O; al Sandouk-Lincke, N A; Schwarzbauer, J

    2014-07-01

    Due to the very limited number of studies dealing with the chemical composition of industrial wastewaters, many industrial organic contaminants still escape our view and consequently also our control. We present here the chemical characterization of wastewaters from different units of a chemical complex, thereby contributing to the characterization of industrial pollution sources. The chemicals produced in the investigated complex are widely and intensively used and the synthesis processes are common and applied worldwide. The chemical composition of untreated and treated wastewaters from the chemical complex was investigated by applying a non-target screening which allowed for the identification of 39 organic contaminants. According to their application most of them belonged to four groups: (i) unspecific educts or intermediates of industrial syntheses, (ii) chemicals for the manufacturing of pharmaceuticals, (iii) educts for the synthesis of polymers and resins, and (iv) compounds known as typical constituents of municipal sewage. A number of halogenated compounds with unknown toxicity and with very high molecular diversity belonged to the second group. Although these compounds were completely removed or degraded during wastewater treatment, they could be useful as "alarm indicators" for industrial accidents in pharmaceutical manufacturing units or for malfunctions of wastewater treatment plants. Three potential branch-specific indicators for polymer manufacturing were found in the outflow of the complex. Among all compounds, bisphenol A, which was present in the leachate water of the on-site waste deposit, occurred in the highest concentrations of up to 20 000 μg L(-1). The comparison of contaminant loads in the inflow and outflow of the on-site wastewater treatment facility showed that most contaminants were completely or at least significantly removed or degraded during the treatment, except two alkylthiols, which were enriched during the treatment process

  18. Floating-type microbial fuel cell (FT-MFC) for treating organic-contaminated water.

    PubMed

    An, Junyeong; Kim, Daehee; Chun, Youngpil; Lee, Soo-Jin; Ng, How Y; Chang, In Seop

    2009-03-01

    This study examines a floating-type microbial fuel cell (FT-MFC) that can be applied to treat organic-contaminated water without mechanical aid. The bottom of the anode compartment was left open to the aquatic environment and the cathode was exposed above the water surface. When four FT-MFCs were inoculated with anaerobic digest fluid (ADF) obtained from a brewery wastewater treatment system (Gwangju, Korea), the open circuit voltages were around 0.4-0.5 V. The initial chemical oxygen demand (COD) of ADF was 1700 ppm and decreased to 380 ppm over a 2-day period under the open circuit mode. Two of the four FT-MFCs were then switched to closed circuit mode to view the current production under batch operation. The current developed was around 0.25 mA and the COD value decreased to 230 ppm after 5 days. The acetate concentration used was varied from 5 to 50 mM to observe whether or notthe substrate was limited bythe growth of bacteria involved in current generation. It was found that the current was maximized at 0.67 mA when 5 mM of acetate was fed at a feeding rate of 0.08 mL/min. Maximum current density and maximum power density were 138 mA/m2 and 8 mW/m2, respectively. These results indicate that FT-MFCs could be applied in situ to treat organic-contaminated water in natural aquatic environments without mechanical aid. Further cathode operation optimization is expected to enhance the treatment of organic materials and corresponding current production.

  19. Sorption mechanism and predictive models for removal of cationic organic contaminants by cation exchange resins.

    PubMed

    Jadbabaei, Nastaran; Zhang, Huichun

    2014-12-16

    Understanding the sorption mechanism of organic contaminants on cation exchange resins (CXRs) will enable application of these resins for the removal of cationic organic compounds from contaminated water. In this study, sorption of a diverse set of 12 organic cations and 8 neutral aromatic solutes on two polystyrene CXRs, MN500 and Amberlite 200, was examined. MN500 showed higher sorbed concentrations due to its microporous structure. The sorbed concentrations followed the same trend of aromatic cations > aliphatic cations > neutral solutes for both resins. Generally, solute-solvent interactions, nonpolar moiety of the solutes, and resin matrix can affect selectivity of the cations. Sorbed concentrations of the neutral compounds were significantly less than those of the cations, indicating a combined effect of electrostatic and nonelectrostatic interactions. By conducting multiple linear regression between Gibbs free energy of sorption and Abraham descriptors for all 20 compounds, polarity/polarizability (S), H-bond acidity (A), induced dipole (E), and electrostatic (J(+)) interactions were found to be involved in the sorption of the cations by the resins. After converting the aqueous sorption isotherms to sorption from the ideal gas-phase by water-wet resins, a more significant effect of J(+) was observed. Predictive models were then developed based on the linear regressions and validated by accurately estimating the sorption of different test set compounds with a root-mean-square error range of 0.91-1.1 and 0.76-0.85 for MN500 and Amberlite 200, respectively. The models also accurately predicted sorption behavior of aniline and imidazole between pH 3 and 10. PMID:25409479

  20. Distribution of potentially bioavailable natural organic carbon in aquifer sediments at a chloroethene-contaminated site

    USGS Publications Warehouse

    Thomas, L.K.; Widdowson, M.A.; Chapelle, F.H.; Novak, J.T.; Boncal, J.E.; Lebrón, C. A.

    2012-01-01

    The distribution of natural organic carbon was investigated at a chloroethene-contaminated site where complete reductive dechlorination of tetrachloroethene (PCE) to vinyl chloride and ethene was observed. In this study, operationally defined potentially bioavailable organic carbon (PBOC) was measured in surficial aquifer sediment samples collected at varying depths and locations in the vicinity of a dense nonaqueous phase liquid (DNAPL) source and aqueous phase plume. The relationship between chloroethene concentrations and PBOC levels was examined by comparing differences in extractable organic carbon in aquifer sediments with minimal chloroethene exposure relative to samples collected in the source zone. Using performance-monitoring data, direct correlations with PBOC were also developed with chloroethene concentrations in groundwater. Results show a logarithm-normal distribution for PBOC in aquifer sediments with a mean concentration of 187  mg/kg. PBOC levels in sediments obtained from the underlying confining unit were generally greater when compared to sediments collected in the sandy surficial aquifer. Results demonstrated a statistically significant inverse correlation (p=0.007) between PBOC levels in aquifer sediments and chloroethene concentrations for selected monitoring wells in which chloroethene exposure was the highest. Results from laboratory exposure assays also demonstrated that sediment samples exhibited a reduction in PBOC levels of 35% and 73%, respectively, after a 72-h exposure period to PCE (20,000  μg/L). These results support the notion that PBOC depletion in sediments may be expected in chloroethene-contaminated aquifers, which has potential implications for the long-term sustainability of monitored natural attenuation.

  1. Influence of dissimilatory metal reduction on fate of organic and metal contaminants in the subsurface

    NASA Astrophysics Data System (ADS)

    Lovley, Derek R.; Anderson, Robert T.

    Dissimilatory Fe(III)-reducing microorganisms have the ability to destroy organic contaminants under anaerobic conditions by oxidizing them to carbon dioxide. Some Fe(III)-reducing microorganisms can also reductively dechlorinate chlorinated contaminants. Fe(III)-reducing microorganisms can reduce a variety of contaminant metals and convert them from soluble forms to forms that are likely to be immobilized in the subsurface. Studies in petroleum-contaminated aquifers have demonstrated that Fe(III)-reducing microorganisms can be effective agents in removing aromatic hydrocarbons from groundwater under anaerobic conditions. Laboratory studies have demonstrated the potential for Fe(III)-reducing microorganisms to remove uranium from contaminated groundwaters. The activity of Fe(III)-reducing microorganisms can be stimulated in several ways to enhance organic contaminant oxidation and metal reduction. Molecular analyses in both field and laboratory studies have demonstrated that microorganisms of the genus Geobacter become dominant members of the microbial community when Fe(III)-reducing conditions develop as the result of organic contamination, or when Fe(III) reduction is artificially stimulated. These results suggest that further understanding of the ecophysiology of Geobacter species would aid in better prediction of the natural attenuation of organic contaminants under anaerobic conditions and in the design of strategies for the bioremediation of subsurface metal contamination. Des micro-organismes simulant la réduction du fer ont la capacité de détruire des polluants organiques dans des conditions anérobies en les oxydant en dioxyde de carbone. Certains micro-organismes réducteurs de fer peuvent aussi dé-chlorer par réduction des polluants chlorés. Des micro-organismes réducteurs de fer peuvent réduire tout un ensemble de métaux polluants et les faire passer de formes solubles à des formes qui sont susceptibles d'être immobilisées dans le milieu

  2. Influence of dissimilatory metal reduction on fate of organic and metal contaminants in the subsurface

    NASA Astrophysics Data System (ADS)

    Lovley, Derek R.; Anderson, Robert T.

    Dissimilatory Fe(III)-reducing microorganisms have the ability to destroy organic contaminants under anaerobic conditions by oxidizing them to carbon dioxide. Some Fe(III)-reducing microorganisms can also reductively dechlorinate chlorinated contaminants. Fe(III)-reducing microorganisms can reduce a variety of contaminant metals and convert them from soluble forms to forms that are likely to be immobilized in the subsurface. Studies in petroleum-contaminated aquifers have demonstrated that Fe(III)-reducing microorganisms can be effective agents in removing aromatic hydrocarbons from groundwater under anaerobic conditions. Laboratory studies have demonstrated the potential for Fe(III)-reducing microorganisms to remove uranium from contaminated groundwaters. The activity of Fe(III)-reducing microorganisms can be stimulated in several ways to enhance organic contaminant oxidation and metal reduction. Molecular analyses in both field and laboratory studies have demonstrated that microorganisms of the genus Geobacter become dominant members of the microbial community when Fe(III)-reducing conditions develop as the result of organic contamination, or when Fe(III) reduction is artificially stimulated. These results suggest that further understanding of the ecophysiology of Geobacter species would aid in better prediction of the natural attenuation of organic contaminants under anaerobic conditions and in the design of strategies for the bioremediation of subsurface metal contamination. Des micro-organismes simulant la réduction du fer ont la capacité de détruire des polluants organiques dans des conditions anérobies en les oxydant en dioxyde de carbone. Certains micro-organismes réducteurs de fer peuvent aussi dé-chlorer par réduction des polluants chlorés. Des micro-organismes réducteurs de fer peuvent réduire tout un ensemble de métaux polluants et les faire passer de formes solubles à des formes qui sont susceptibles d'être immobilisées dans le milieu

  3. Remediation of RDX- and HMX-contaminated groundwater using organic mulch permeable reactive barriers.

    PubMed

    Ahmad, Farrukh; Schnitker, Stephen P; Newell, Charles J

    2007-02-20

    Organic mulch is a complex organic material that is typically populated with its own consortium of microorganisms. The organisms in mulch breakdown complex organics to soluble carbon, which can then be used by these and other microorganisms as an electron donor for treating RDX and HMX via reductive pathways. A bench-scale treatability study with organic mulch was conducted for the treatment of RDX- and HMX-contaminated groundwater obtained from a plume at the Pueblo Chemical Depot (PCD) in Pueblo, Colorado. The site-specific cleanup criteria of 0.55 ppb RDX and 602 ppb HMX were used as the logical goals of the study. Column flow-through tests were run to steady-state at the average site seepage velocity, using a 70%:30% (vol.:vol.) mulch:pea gravel packing to approach the formation's permeability. Significant results included: (1) Complete removal of 90 ppb influent RDX and 8 ppb influent HMX in steady-state mulch column effluent; (2) pseudo-first-order steady-state kinetic rate constant, k, of 0.20 to 0.27 h(-1) based on RDX data, using triplicate parallel column runs; (3) accumulation of reduced RDX intermediates in the steady-state column effluent at less than 2% of the influent RDX mass; (4) no binding of RDX to the column fill material; and (5) no leaching of RDX, HMX or reduction intermediates from the column fill material. The results of the bench-scale study will be used to design and implement a pilot-scale organic mulch/pea gravel permeable reactive barrier (PRB) at the site.

  4. Remediation of RDX- and HMX-contaminated groundwater using organic mulch permeable reactive barriers

    NASA Astrophysics Data System (ADS)

    Ahmad, Farrukh; Schnitker, Stephen P.; Newell, Charles J.

    2007-02-01

    Organic mulch is a complex organic material that is typically populated with its own consortium of microorganisms. The organisms in mulch breakdown complex organics to soluble carbon, which can then be used by these and other microorganisms as an electron donor for treating RDX and HMX via reductive pathways. A bench-scale treatability study with organic mulch was conducted for the treatment of RDX- and HMX-contaminated groundwater obtained from a plume at the Pueblo Chemical Depot (PCD) in Pueblo, Colorado. The site-specific cleanup criteria of 0.55 ppb RDX and 602 ppb HMX were used as the logical goals of the study. Column flow-through tests were run to steady-state at the average site seepage velocity, using a 70%:30% (vol.:vol.) mulch:pea gravel packing to approach the formation's permeability. Significant results included: (1) Complete removal of 90 ppb influent RDX and 8 ppb influent HMX in steady-state mulch column effluent; (2) pseudo-first-order steady-state kinetic rate constant, k, of 0.20 to 0.27 h - 1 based on RDX data, using triplicate parallel column runs; (3) accumulation of reduced RDX intermediates in the steady-state column effluent at less than 2% of the influent RDX mass; (4) no binding of RDX to the column fill material; and (5) no leaching of RDX, HMX or reduction intermediates from the column fill material. The results of the bench-scale study will be used to design and implement a pilot-scale organic mulch/pea gravel permeable reactive barrier (PRB) at the site.

  5. Adsorption of organic contaminants by graphene nanosheets, carbon nanotubes and granular activated carbons under natural organic matter preloading conditions.

    PubMed

    Ersan, Gamze; Kaya, Yasemin; Apul, Onur G; Karanfil, Tanju

    2016-09-15

    The effect of NOM preloading on the adsorption of phenanthrene (PNT) and trichloroethylene (TCE) by pristine graphene nanosheets (GNS) and graphene oxide nanosheet (GO) was investigated and compared with those of a single-walled carbon nanotube (SWCNT), a multi-walled carbon nanotube (MWCNT), and two coal based granular activated carbons (GACs). PNT uptake was higher than TCE by all adsorbents on both mass and surface area bases. This was attributed to the hydrophobicity of PNT. The adsorption capacities of PNT and TCE depend on the accessibility of the organic molecules to the inner regions of the adsorbent which was influenced from the molecular size of OCs. The adsorption capacities of all adsorbents decreased as a result of NOM preloading due to site competition and/or pore/interstice blockage. However, among all adsorbents, GO was generally effected least from the NOM preloading for PNT, whereas there was not observed any trend of NOM competition with a specific adsorbent for TCE. In addition, SWCNT was generally affected most from the NOM preloading for TCE and there was not any trend for PNT. The overall results indicated that the fate and transport of organic contaminants by GNSs and CNTs type of nanoadsorbents and GACs in different natural systems will be affected by water quality parameters, characteristics of adsorbent, and properties of adsorbate.

  6. Adsorption of organic contaminants by graphene nanosheets, carbon nanotubes and granular activated carbons under natural organic matter preloading conditions.

    PubMed

    Ersan, Gamze; Kaya, Yasemin; Apul, Onur G; Karanfil, Tanju

    2016-09-15

    The effect of NOM preloading on the adsorption of phenanthrene (PNT) and trichloroethylene (TCE) by pristine graphene nanosheets (GNS) and graphene oxide nanosheet (GO) was investigated and compared with those of a single-walled carbon nanotube (SWCNT), a multi-walled carbon nanotube (MWCNT), and two coal based granular activated carbons (GACs). PNT uptake was higher than TCE by all adsorbents on both mass and surface area bases. This was attributed to the hydrophobicity of PNT. The adsorption capacities of PNT and TCE depend on the accessibility of the organic molecules to the inner regions of the adsorbent which was influenced from the molecular size of OCs. The adsorption capacities of all adsorbents decreased as a result of NOM preloading due to site competition and/or pore/interstice blockage. However, among all adsorbents, GO was generally effected least from the NOM preloading for PNT, whereas there was not observed any trend of NOM competition with a specific adsorbent for TCE. In addition, SWCNT was generally affected most from the NOM preloading for TCE and there was not any trend for PNT. The overall results indicated that the fate and transport of organic contaminants by GNSs and CNTs type of nanoadsorbents and GACs in different natural systems will be affected by water quality parameters, characteristics of adsorbent, and properties of adsorbate. PMID:27107611

  7. Approaches to mitigate the impact of dissolved organic matter on the adsorption of synthetic organic contaminants by porous carbonaceous sorbents

    SciTech Connect

    Yanping Guo; Abhishek Yadav; Tanju Karanfil

    2007-11-15

    Adsorption of trichloroethylene (TCE) and atrazine, two synthetic organic contaminants (SOCs) having different optimum adsorption pore regions, by four activated carbons and an activated carbon fiber (ACF) was examined. Adsorbents included two coconut-shell based granular activated carbons (GACs), two coal-based GACs (F400 and HD4000) and a phenol formaldehyde-based activated carbon fiber. The selected adsorbents had a wide range of pore size distributions but similar surface acidity and hydrophobicity. Single solute and preloading (with a dissolved organic matter (DOM)) isotherms were performed. Single solute adsorption results showed that (i) the adsorbents having higher amounts of pores with sizes about the dimensions of the adsorbate molecules exhibited higher uptakes, (ii) there were some pore structure characteristics, which were not completely captured by pore size distribution analysis, that also affected the adsorption, and (iii) the BET surface area and total pore volume were not the primary factors controlling the adsorption of SOCs. The preloading isotherm results showed that for TCE adsorbing primarily in pores <10 {angstrom}, the highly microporous ACF and GACs, acting like molecular sieves, exhibited the highest uptakes. For atrazine with an optimum adsorption pore region of 10-20 {angstrom}, which overlaps with the adsorption region of some DOM components, the GACs with a broad pore size distribution and high pore volumes in the 10-20 {angstrom} region had the least impact of DOM on the adsorption. 25 refs., 3 figs., 3 tabs.

  8. Hepatotoxicity and nephrotoxicity of organic contaminants in wastewater-irrigated soil.

    PubMed

    Gao, Hongxia; Liu, Yingli; Guan, Weijun; Li, Qingzhao; Liu, Nan; Gao, Zhenjie; Fan, Jianjun

    2015-03-01

    The objective of this study is to investigate the hepatotoxicity and nephrotoxicity of organic contaminants in wastewater-irrigated soil using in vivo and in vitro experiments on mice and rat. Soil samples were collected from a wastewater-irrigated area and groundwater-irrigated area, i.e. clean water-irrigated area as control group. The organic contaminants were extracted using an ultrasonic oscillator. In vivo experiment was performed by contamination of hepatocytes of rat using the organic extract, and comet assay was used to analyse the DNA damage of hepatocytes. For in vitro experiment, mice were first gavaged with extracts, and then the indicators for kidney functions, liver functions and oxidative damage of tissues were investigated. The result shows, for in vitro experiments, compared with clean water-irrigated area groups, the average DNA tailing length for the wastewater-irrigated area group is larger, and for the wastewater-irrigated area groups with extract concentration 0.6 g/ml and 0.9 g/ml, the tailing rate increases significantly (P < 0.05). For in vivo experiments, the change of weight across each group shows no significant difference (P < 0.05). Compared with clean water-irrigated groups, the liver indices have decreased for all groups of the wastewater-irrigated area, while both kidney and liver indices decreased for wastewater-irrigated area high-dose group (P < 0.05 or P < 0.01). The total proteins for wastewater-irrigated low-dose group and Gamma-glutamyl transpeptidase, creatinine for high-dose group all increased (P < 0.01). Compared with the reagent control group, total superoxide dismutase activity of liver for wastewater-irrigated groups and glutathione peroxidase activity for high-dose group, malondialdehyde content all decreased (P < 0.05 or P < 0.01); glutathione peroxidase activity of kidney tissue for wastewater-irrigated high-dose group decreased (P < 0.01). The result shows that the joint toxicity in

  9. Impact of urbanization on the concentrations and distribution of organic contaminants in boreal lake sediments.

    PubMed

    Honkonen, Olga; Rantalainen, Anna-Lea

    2013-02-01

    The main goal of this study was to evaluate the impacts of a middle-sized Finnish urban area on the quality of sediments in an adjacent boreal lake. We investigated the sources and distribution of organic pollutants (polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs)) in the sediments from urban stormwater traps and from Lake Vesijärvi. Grab surface sediment samples were taken from Lake Vesijärvi at various distances (25-2,000 m) from four major stormwater drainage outlets and at 15 urban stormwater traps in areas with different degrees of urbanization. These samples were analysed for 16 PAHs and 28 PCBs with gas chromatography-mass spectrometry. The concentrations of pollutants in the lake sediments were elevated in the vicinity of the urban shore (∑PAH 3-16, ∑PCB up to 0.02-0.3 mg/kg dw) and decreased as a function of distance (∑PAH 0.1-2.5, ∑PCB 0.01-0.3 mg/kg dw at a distance of more than 500 m from the shore), whereas contamination levels in suburban areas were notably lower (∑PAH 0.1-3, ∑PCB < LOQ-0.03 mg/kg dw; did not decline with distance). Possible sources and pathways of contamination were also investigated. The majority of stormwater trap sediments contained predominantly asphalt-derived PAHs due to pulverized pavement. PAHs in lake sediments were of pyrogenic origin, including the combustion of gasoline, diesel and coal. Suggested pathways of lake contamination are urban runoff discharge, boat traffic and atmospheric deposition.

  10. Stable isotope fractionation to investigate natural transformation mechanisms of organic contaminants: principles, prospects and limitations.

    PubMed

    Elsner, Martin

    2010-11-01

    Gas chromatography-isotope ratio mass spectrometry (GC-IRMS) has made it possible to analyze natural stable isotope ratios (e.g., (13)C/(12)C, (15)N/(14)N, (2)H/(1)H) of individual organic contaminants in environmental samples. They may be used as fingerprints to infer contamination sources, and may demonstrate, and even quantify, the occurrence of natural contaminant transformation by the enrichment of heavy isotopes that arises from degradation-induced isotope fractionation. This review highlights an additional powerful feature of stable isotope fractionation: the study of environmental transformation mechanisms. Isotope effects reflect the energy difference of isotopologues (i.e., molecules carrying a light versus a heavy isotope in a particular molecular position) when moving from reactant to transition state. Measuring isotope fractionation, therefore, essentially allows a glimpse at transition states! It is shown how such position-specific isotope effects are "diluted out" in the compound average measured by GC-IRMS, and how a careful evaluation in mechanistic scenarios and by dual isotope plots can recover the underlying mechanistic information. The mathematical framework for multistep isotope fractionation in environmental transformations is reviewed. Case studies demonstrate how isotope fractionation changes in the presence of mass transfer, enzymatic commitment to catalysis, multiple chemical reaction steps or limited bioavailability, and how this gives information about the individual process steps. Finally, it is discussed how isotope ratios of individual products evolve in sequential or parallel transformations, and what mechanistic insight they contain. A concluding session gives an outlook on current developments, future research directions and the potential for bridging the gap between laboratory and real world systems.

  11. Identifying sources of emerging organic contaminants in a mixed use watershed using principal components analysis.

    PubMed

    Karpuzcu, M Ekrem; Fairbairn, David; Arnold, William A; Barber, Brian L; Kaufenberg, Elizabeth; Koskinen, William C; Novak, Paige J; Rice, Pamela J; Swackhamer, Deborah L

    2014-01-01

    Principal components analysis (PCA) was used to identify sources of emerging organic contaminants in the Zumbro River watershed in Southeastern Minnesota. Two main principal components (PCs) were identified, which together explained more than 50% of the variance in the data. Principal Component 1 (PC1) was attributed to urban wastewater-derived sources, including municipal wastewater and residential septic tank effluents, while Principal Component 2 (PC2) was attributed to agricultural sources. The variances of the concentrations of cotinine, DEET and the prescription drugs carbamazepine, erythromycin and sulfamethoxazole were best explained by PC1, while the variances of the concentrations of the agricultural pesticides atrazine, metolachlor and acetochlor were best explained by PC2. Mixed use compounds carbaryl, iprodione and daidzein did not specifically group with either PC1 or PC2. Furthermore, despite the fact that caffeine and acetaminophen have been historically associated with human use, they could not be attributed to a single dominant land use category (e.g., urban/residential or agricultural). Contributions from septic systems did not clarify the source for these two compounds, suggesting that additional sources, such as runoff from biosolid-amended soils, may exist. Based on these results, PCA may be a useful way to broadly categorize the sources of new and previously uncharacterized emerging contaminants or may help to clarify transport pathways in a given area. Acetaminophen and caffeine were not ideal markers for urban/residential contamination sources in the study area and may need to be reconsidered as such in other areas as well. PMID:25135154

  12. Column experiment to study isotope fractionation of volatile organic contaminants in porous media under unsaturated conditions

    NASA Astrophysics Data System (ADS)

    Jeannottat, Simon; Hunkeler, Daniel; Breider, Florian

    2010-05-01

    Pollution by organic contaminants such as petroleum hydrocarbons and chlorinated solvents is common in industrialized countries. The use of stable isotope analysis is increasingly recognized as a powerful technique for investigating the behaviour of organic or inorganic contaminants. Recently, compound-specific isotope analysis (CSIA) has proven to be an effective tool to confirm and quantify in-situ biodegradation by indigenous microbial populations in groundwater.In contrast, only few studies have investigated the use of CSIA in the unsaturated zone. In the unsaturated zone, the main potential applications of CSIA include the assessment of biodegradation and the fingerprinting of different sources of petroleum hydrocarbon or chlorinated solvents vapours. However, it has to be taken into account that isotope ratios in the unsaturated zone can vary due to diffusion and volatilization in addition to biodegradation. For application of isotope methods in the unsaturated zone, it is crucial to quantify isotopic fractionation resulting from physico-chemical and transport processes. The study is focused on laboratory experiments that investigate the effect of vaporization and diffusion on isotope ratios. The effect of diffusion is carried out using a column experiment setup that can be considered to represent VOC transport from a floating NAPL towards the atmosphere. Furthermore, additional column and batch experiments will be conducted to better understand the effect of biodegradation. Volatilization is studied with an other experimental setup. In addition, a mathematical framework was developed to simulate the isotope evolution in the column study. Since the initial experiments aimed at investigating the effect of vaporization and diffusion only, the column is filled with dry quartz sand in order to avoid perturbations of concentration profiles by humidity or adsorption on organic matter. An activated sand will later be used for the biodegradation experiments. A

  13. Development of HUMASORB{trademark}, a lignite derived humic acid for removal of metals and organic contaminants from groundwater

    SciTech Connect

    Sanjay, H.G.; Tiedje, M.; Stashick, J.J.; Srivastava, K.C.; Johnson, H.R.; Walia, D.S.

    1996-12-31

    Heavy metal and organic contamination of surface and groundwater is a major environmental concern. The contamination is primarily due to improperly disposed industrial wastes. Decontamination of surface and groundwater can be achieved using a broad spectrum of treatment options such as precipitation, ion-exchange, microbial digestion, membrane separation, activated carbon adsorption, etc. The state-of-the-art technologies for treatment of contaminated water, however, can in one pass remediate only one class of contaminants, i.e., either VOCs (activated carbon) or heavy metals( ion-exchange). The groundwater contamination at different Department of Energy (DOE) sites (e.g. Hanford) is due to the presence of both VOCs and heavy metals. Therefore, two different stepwise processes are needed to remediate a site. The two-step approach increases the cost of remediation. A novel material having properties to remove both classes of contaminants in one step is being developed as part of this project. The objective of this project is to develop a lignite derived adsorbent, HUMASORB{sup TM}, to remove heavy metal and organic contaminants from groundwater and surface water streams in one processing step. As part of this project, HUMASORB{sup TM} is being characterized and evaluated for its ion-exchange and adsorption capabilities.

  14. Contaminant transport in dual-porosity media with dissolved organic matter and bacteria present as mobile colloids.

    PubMed

    Kim, Song-Bae; Corapcioglu, M Yavuz

    2002-12-01

    In riverbank filtration, contaminant transport is affected by colloidal particles such as dissolved organic matter (DOM) and bacterial particles. In addition, the subsurface heterogeneity influences the behavior of contaminant transport in riverbank filtration. A mathematical model is developed to describe the contaminant transport in dual-porosity media in the presence of DOM and bacteria as mobile colloids. In the model development, a porous medium is divided into the mobile and immobile regions to consider the presence of ineffective micropores in physically heterogeneous riverbanks. We assume that the contaminant transport in the mobile region is controlled by the advection and dispersion while the contaminant transport in the immobile region occurs due to the molecular diffusion. The contaminant transfer between the mobile and immobile regions takes place by diffusive mass transfer. The mobile region is conceptualized as a four-phase system: two mobile colloidal phases, an aqueous phase, and a solid matrix. The complete set of governing equations is solved numerically with a fully implicit finite difference method. The model results show that in riverbank filtration, the contaminant can migrate further than expected due to the presence of DOM and bacteria. In addition, the contaminant mobility increases further in the presence of the immobile region in aquifers. A sensitivity analysis shows that in dual-porosity media, earlier breakthrough of the contaminant takes place as the volumetric fraction of the mobile region decreases. It is also demonstrated that as the contaminant mass transfer rate coefficient between the mobile and immobile regions increases, the contaminant concentration gradient between the two regions reverses at earlier pore volumes. The contaminant mass transfer coefficient between the mobile and immobile regions mainly controls the tailing effect of the contaminant breakthrough. The contaminant breakthrough curves are sensitive to changes in

  15. Contaminant transport in dual-porosity media with dissolved organic matter and bacteria present as mobile colloids.

    PubMed

    Kim, Song-Bae; Corapcioglu, M Yavuz

    2002-12-01

    In riverbank filtration, contaminant transport is affected by colloidal particles such as dissolved organic matter (DOM) and bacterial particles. In addition, the subsurface heterogeneity influences the behavior of contaminant transport in riverbank filtration. A mathematical model is developed to describe the contaminant transport in dual-porosity media in the presence of DOM and bacteria as mobile colloids. In the model development, a porous medium is divided into the mobile and immobile regions to consider the presence of ineffective micropores in physically heterogeneous riverbanks. We assume that the contaminant transport in the mobile region is controlled by the advection and dispersion while the contaminant transport in the immobile region occurs due to the molecular diffusion. The contaminant transfer between the mobile and immobile regions takes place by diffusive mass transfer. The mobile region is conceptualized as a four-phase system: two mobile colloidal phases, an aqueous phase, and a solid matrix. The complete set of governing equations is solved numerically with a fully implicit finite difference method. The model results show that in riverbank filtration, the contaminant can migrate further than expected due to the presence of DOM and bacteria. In addition, the contaminant mobility increases further in the presence of the immobile region in aquifers. A sensitivity analysis shows that in dual-porosity media, earlier breakthrough of the contaminant takes place as the volumetric fraction of the mobile region decreases. It is also demonstrated that as the contaminant mass transfer rate coefficient between the mobile and immobile regions increases, the contaminant concentration gradient between the two regions reverses at earlier pore volumes. The contaminant mass transfer coefficient between the mobile and immobile regions mainly controls the tailing effect of the contaminant breakthrough. The contaminant breakthrough curves are sensitive to changes in

  16. Hydrous pyrolysis/oxidation: in-ground thermal destruction of organic contaminants

    SciTech Connect

    Knauss, K. G.; Aines, R.D.; Dibley, M.J.; Leif, R.N.; Mew, D.A.

    1997-03-11

    Experimental work with organic solvents at Lawrence Livermore National Laboratory has suggested that in situ thermal oxidation of these compounds via hydrous pyrolysis forms the basis for a whole new remediation method, called hydrous pyrolysis oxidation. Preliminary results of hydrothermal oxidation using both dissolved 0{sub 2} gas and mineral oxidants present naturally in soils (e.g., MnO{sub 2}) demonstrate that TCE, TCA, and even PCE can be rapidly and completely degraded to benign products at moderate conditions, easily achieved in thermal remediation. Polycyclic aromatic hydrocarbons (PAHS) have an even larger thermodynamic driving force favoring oxidation, and they are also amenable to in situ destruction. Today, the principal treatment methods for chlorinated solvent- and PAH-contaminated soil are to remove it to landfills, or incinerate it on site. The most effective method for treating ground water, Dynamic Underground Stripping (Newmark et al., 1995), still involves removing the contaminant for destruction elsewhere. Hydrous pyrolysis/oxidation would eliminate the need for long-term use of expensive treatment facilities by converting all remaining contaminant to benign products (e.g., carbon dioxide, water, and chloride ion). The technique is expected to be applicable to dense non-aqueous phase liquids (DNAPLS) and dissolved organic components. Soil and ground water would be polished without bringing them to the surface. This would dramatically decrease the cost of final site closure efforts. Large-scale cleanup using hydrous pyrolysis/oxidation may cost less than $10/yd. The end product of hydrous pyrolysis/oxidation is expected to be a clean site. The delivery concept for hydrous pyrolysis/oxidation utilizes the established experience in heating large volumes of ground developed in the Dynamic Underground Stripping Demonstration (Newmark et al., 1995). Steam and possibly oxygen are injected together, building a heated, oxygenated zone in the

  17. Reclamation of a mine contaminated soil using biologically reactive organic matrices.

    PubMed

    Alvarenga, Paula; Gonçalves, Ana Paula; Fernandes, Rosa Maria; de Varennes, Amarillas; Duarte, Elizabeth; Cunha-Queda, Ana Cristina; Vallini, Giovanni

    2009-03-01

    Organic residues such as sewage sludge, biowastes and composts are increasingly used in land rehabilitation because they can improve the physical, chemical and biochemical properties of soil, and reduce the need for inorganic fertilization. Furthermore, their use contributes to an integrated approach to waste management by promoting recycling of nutrients and minimizing final disposal, especially of organic residues that, due to their composition, can pose problems to agricultural soils. In the present study, three different types of organic residues were considered as amendments to be used in the reclamation of a metal-contaminated mine soil from the Aljustrel mining area (a pyrite mine located in the SW Portugal in the Iberian Pyrite Belt), with high Cu, Pb and Zn total contents: sewage sludge from a municipal wastewater treatment plant (SS), compost from the organic fraction of unsorted municipal solid waste (MSWC), and garden waste compost (GWC), applied at 100 and 200 Mg ha(-1) . The soil and mixtures of soil and amendments were adjusted to 70% of the maximum water-holding capacity determined for each type of sample and incubated in a controlled-temperature room at 20 +/- 1 degrees C. Sub-samples were taken prior to wetting (time zero), and after 7, 14, 21 and 28 days of incubation, and analysed for pH, electrical conductivity, organic matter content, effectively bioavailable Cu, Zn and Pb (extracted with 0.01 mol L(- 1) calcium chloride) and potentially bioavailable metals (extracted with 0.5 mol L(-1) ammonium acetate, 0.5 mol L( -1) acetic acid and 0.01 mol L(- 1) EDTA, pH 4.7). In general, organic residues corrected soil acidity, and increased the total organic matter content of the soil. The SS and the MSWC amendments were roughly equivalent in their ability to correct soil acidity whereas the GWC had the smallest liming capacity and only with 200 Mg ha(-1) GWC did the soil pH reach acceptable values. As expected, all the tested organic residues, at both

  18. Effects of organic carbon supply rates on mobility of previously bioreduced uranium in a contaminated sediment

    SciTech Connect

    Wan, J.; Tokunaga, T.K.; Kim, Y.; Brodie, E.; Daly, R.; Hazen, T.C.; Firestone, M.K.

    2008-05-15

    Bioreduction-based strategies for remediating uranium (U)-contaminated sediments face the challenge of maintaining the reduced status of U for long times. Because groundwater influxes continuously bring in oxidizing terminal electron acceptors (O{sub 2}, NO{sub 3}{sup -}), it is necessary to continue supplying organic carbon (OC) to maintain the reducing environment after U bioreduction is achieved. We tested the influence of OC supply rates on mobility of previously microbial reduced uranium U(IV) in contaminated sediments. We found that high degrees of U mobilization occurred when OC supply rates were high, and when the sediment still contained abundant Fe(III). Although 900 days with low levels of OC supply minimized U mobilization, the sediment redox potential increased with time as did extractable U(VI) fractions. Molecular analyses of total microbial activity demonstrated a positive correlation with OC supply and analyses of Geobacteraceae activity (RT-qPCR of 16S rRNA) indicated continued activity even when the effluent Fe(II) became undetectable. These data support our earlier hypothesis on the mechanism responsible for re-oxidation of microbial reduced U(IV) under reducing conditions; that microbial respiration caused increased (bi)carbonate concentrations and formation of stable uranyl carbonate complexes, thereby shifted U(IV)/U(VI) equilibrium to more reducing potentials. The data also suggested that low OC concentrations could not sustain the reducing condition of the sediment for much longer time.

  19. Effects of dissolved organic matter on the co-transport of mineral colloids and sorptive contaminants.

    PubMed

    Cheng, Tao; Saiers, James E

    2015-01-01

    Colloid-facilitated transport of contaminants in the vadose zone has important implications to groundwater quality, and has received considerable attention. Natural organic matter (NOM) is ubiquitous in subsurface environments, and its influence on mineral colloids and solute transport has been well documented. However, research on the influence of NOM on colloid-facilitated transport is limited. The objective of this paper is to elucidate the effects of NOM on colloid-facilitated transport of a radioactive contaminant (Cs-137) within partially-saturated sediments. Measurements made with re-packed columns reveal that Cs-137 mobility was low when mineral colloids were absent and was unaffected by the presence of NOM. The addition of mineral colloids to influent increased Cs-137 mobility, and effluent Cs-137 was dominated by the colloid-associated form. When NOM was added to systems that contained mineral colloids and Cs-137, the mobility of Cs-137 further increased. A mathematical model simulating colloid-facilitated transport showed that NOM increases Cs-137 transport by increasing colloid mobility and reducing the rate of Cs-137 adsorption to the porous medium.

  20. A national reconnaissance of pharmaceuticals and other organic wastewater contaminants in the United States - I) Groundwater

    USGS Publications Warehouse

    Barnes, K.K.; Kolpin, D.W.; Furlong, E.T.; Zaugg, S.D.; Meyer, M.T.; Barber, L.B.

    2008-01-01

    As part of the continuing effort to collect baseline information on the environmental occurrence of pharmaceuticals, and other organic wastewater contaminants (OWCs) in the Nation's water resources, water samples were collected from a network of 47 groundwater sites across 18 states in 2000. All samples collected were analyzed for 65 OWCs representing a wide variety of uses and origins. Site selection focused on areas suspected to be susceptible to contamination from either animal or human wastewaters (i.e. down gradient of a landfill, unsewered residential development, or animal feedlot). Thus, sites sampled were not necessarily used as a source of drinking water but provide a variety of geohydrologic environments with potential sources of OWCs. OWCs were detected in 81% of the sites sampled, with 35 of the 65 OWCs being found at least once. The most frequently detected compounds include N,N-diethyltoluamide (35%, insect repellant), bisphenol A (30%, plasticizer), tri(2-chloroethyl) phosphate (30%, fire retardant), sulfamethoxazole (23%, veterinary and human antibiotic), and 4-octylphenol monoethoxylate (19%, detergent metabolite). Although sampling procedures were intended to ensure that all groundwater samples analyzed were indicative of aquifer conditions it is possible that detections of some OWCs could have resulted from leaching of well-construction materials and/or other site-specific conditions related to well construction and materials. Future research will be needed to identify those factors that are most important in determining the occurrence and concentrations of OWCs in groundwater.

  1. Organic amendments increase phylogenetic diversity of arbuscular mycorrhizal fungi in acid soil contaminated by trace elements.

    PubMed

    Montiel-Rozas, María Del Mar; López-García, Álvaro; Kjøller, Rasmus; Madejón, Engracia; Rosendahl, Søren

    2016-08-01

    In 1998, a toxic mine spill polluted a 55-km(2) area in a basin southward to Doñana National Park (Spain). Subsequent attempts to restore those trace element-contaminated soils have involved physical, chemical, or biological methodologies. In this study, the restoration approach included application of different types and doses of organic amendments: biosolid compost (BC) and leonardite (LEO). Twelve years after the last addition, molecular analyses of arbuscular mycorrhizal (AM) fungal communities associated with target plants (Lamarckia aurea and Chrysanthemum coronarium) as well as analyses of trace element concentrations both in soil and in plants were performed. The results showed an improved soil quality reflected by an increase in soil pH and a decrease in trace element availability as a result of the amendments and dosages. Additionally, the phylogenetic diversity of the AM fungal community increased, reaching the maximum diversity at the highest dose of BC. Trace element concentration was considered the predominant soil factor determining the AM fungal community composition. Thereby, the studied AM fungal community reflects a community adapted to different levels of contamination as a result of the amendments. The study highlights the long-term effect of the amendments in stabilizing the soil system. PMID:27072359

  2. Medical costs and lost productivity from health conditions at volatile organic compound-contaminated Superfund sites

    SciTech Connect

    Lybarger, J.A.; Spengler, R.F.; Brown, D.R.; Lee, R.; Vogt, D.P. |; Perhac, R.M. Jr. |

    1998-10-01

    This paper estimates the health costs at Superfund sites for conditions associated with volatile organic compounds (VOCs) in drinking water. Health conditions were identified from published literature and registry information as occurring at excess rates in VOC-exposed populations. These health conditions were: (1) some categories of birth defects, (2) urinary tract disorders, (3) diabetes, (4) eczema and skin conditions, (5) anemia, (6) speech and hearing impairments in children under 10 years of age, and (7) stroke. Excess rates were used to estimate the excess number of cases occurring among the total population living within one-half mile of 258 Superfund sites. These sites had evidence of completed human exposure pathways for VOCs in drinking water. For each type of medical condition, an individual`s expected medical costs, long-term care costs, and lost work time due to illness or premature mortality were estimated. Costs were calculated to be approximately $330 million per year, in the absence of any remediation or public health intervention programs. The results indicate the general magnitude of the economic burden associated with a limited number of contaminants at a portion of all Superfund sites, thus suggesting that the burden would be greater than that estimated in this study if all contaminants at all Superfund sites could be taken into account.

  3. Organic amendments increase phylogenetic diversity of arbuscular mycorrhizal fungi in acid soil contaminated by trace elements.

    PubMed

    Montiel-Rozas, María Del Mar; López-García, Álvaro; Kjøller, Rasmus; Madejón, Engracia; Rosendahl, Søren

    2016-08-01

    In 1998, a toxic mine spill polluted a 55-km(2) area in a basin southward to Doñana National Park (Spain). Subsequent attempts to restore those trace element-contaminated soils have involved physical, chemical, or biological methodologies. In this study, the restoration approach included application of different types and doses of organic amendments: biosolid compost (BC) and leonardite (LEO). Twelve years after the last addition, molecular analyses of arbuscular mycorrhizal (AM) fungal communities associated with target plants (Lamarckia aurea and Chrysanthemum coronarium) as well as analyses of trace element concentrations both in soil and in plants were performed. The results showed an improved soil quality reflected by an increase in soil pH and a decrease in trace element availability as a result of the amendments and dosages. Additionally, the phylogenetic diversity of the AM fungal community increased, reaching the maximum diversity at the highest dose of BC. Trace element concentration was considered the predominant soil factor determining the AM fungal community composition. Thereby, the studied AM fungal community reflects a community adapted to different levels of contamination as a result of the amendments. The study highlights the long-term effect of the amendments in stabilizing the soil system.

  4. Stabilization of Rocky Flats combustible residues contaminated with plutonium metal and organic solvents

    SciTech Connect

    Bowen, S.M.; Cisneros, M.R.; Jacobson, L.L.; Schroeder, N.C.; Ames, R.L.

    1998-09-30

    This report describes tests on a proposed flowsheet designed to stabilize combustible residues that were generated at the Rocky Flats Environmental Technology Site (RFETS) during the machining of plutonium metal. Combustible residues are essentially laboratory trash contaminated with halogenated organic solvents and plutonium metal. The proposed flowsheet, designed by RFETS, follows a glovebox procedure that includes (1) the sorting and shredding of materials, (2) a low temperature thermal desorption of solvents from the combustible materials, (3) an oxidation of plutonium metal with steam, and (4) packaging of the stabilized residues. The role of Los Alamos National Laboratory (LANL) in this study was to determine parameters for the low temperature thermal desorption and steam oxidation steps. Thermal desorption of carbon tetrachloride (CCl{sub 4}) was examined using a heated air stream on a Rocky Flats combustible residue surrogate contaminated with CCl{sub 4}. Three types of plutonium metal were oxidized with steam in a LANL glovebox to determine the effectiveness of this procedure for residue stabilization. The results from these LANL experiments are used to recommend parameters for the proposed RFETS stabilization flowsheet.

  5. In vitro cytogenetic studies of organic chemicals found as contaminants in spacecraft cabin atmospheres

    NASA Technical Reports Server (NTRS)

    Torres, J.

    1986-01-01

    Astronauts can be exposed during spaceflight to organic chemical contaminants in the spacecraft cabin atmosphere. Toxic exposures may cause lesions in the cellular DNA which are subsequently expressed as sister-chromatid exchanges (SCE). Analysis of SCE is a sensitive short-term assay technique to detect and quantitate exposures to DNA-damaging (mutagenic) substances. The increase in SCE incidence over baseline (control) levels is generally proportional to the concentration of the mutagen and to the duration of exposure. Dichloromethane (methylene chloride) was chosen for this study since it occurred as an atmospheric contaminant in ten of the first 12 STS flights, and has been reported to have toxic and mutagenic effects in various test systems. Glutaraldehyde was chosen because relatively few data are available on the toxicity or mutagenicity of this common biological fixative, which is carried on STS flights for use in biological experiments. The BHK-21 baby hamster kidney cell line was the in vitro test system used in this study. Neither dichloromethane (10 ppm to 500 ppm) nor glutaraldehyde (1 ppm to 10 ppm) increased SCE levels following 20-hour exposure of BHK-21 cells to the test chemicals.

  6. Effects of dissolved organic matter on the co-transport of mineral colloids and sorptive contaminants

    NASA Astrophysics Data System (ADS)

    Cheng, Tao; Saiers, James E.

    2015-06-01

    Colloid-facilitated transport of contaminants in the vadose zone has important implications to groundwater quality, and has received considerable attention. Natural organic matter (NOM) is ubiquitous in subsurface environments, and its influence on mineral colloids and solute transport has been well documented. However, research on the influence of NOM on colloid-facilitated transport is limited. The objective of this paper is to elucidate the effects of NOM on colloid-facilitated transport of a radioactive contaminant (Cs-137) within partially-saturated sediments. Measurements made with re-packed columns reveal that Cs-137 mobility was low when mineral colloids were absent and was unaffected by the presence of NOM. The addition of mineral colloids to influent increased Cs-137 mobility, and effluent Cs-137 was dominated by the colloid-associated form. When NOM was added to systems that contained mineral colloids and Cs-137, the mobility of Cs-137 further increased. A mathematical model simulating colloid-facilitated transport showed that NOM increases Cs-137 transport by increasing colloid mobility and reducing the rate of Cs-137 adsorption to the porous medium.

  7. Development of surrogate correlation models to predict trace organic contaminant oxidation and microbial inactivation during ozonation.

    PubMed

    Gerrity, Daniel; Gamage, Sujanie; Jones, Darryl; Korshin, Gregory V; Lee, Yunho; Pisarenko, Aleksey; Trenholm, Rebecca A; von Gunten, Urs; Wert, Eric C; Snyder, Shane A

    2012-12-01

    The performance of ozonation in wastewater depends on water quality and the ability to form hydroxyl radicals (·OH) to meet disinfection or contaminant transformation objectives. Since there are no on-line methods to assess ozone and ·OH exposure in wastewater, many agencies are now embracing indicator frameworks and surrogate monitoring for regulatory compliance. Two of the most promising surrogate parameters for ozone-based treatment of secondary and tertiary wastewater effluents are differential UV(254) absorbance (ΔUV(254)) and total fluorescence (ΔTF). In the current study, empirical correlations for ΔUV(254) and ΔTF were developed for the oxidation of 18 trace organic contaminants (TOrCs), including 1,4-dioxane, atenolol, atrazine, bisphenol A, carbamazepine, diclofenac, gemfibrozil, ibuprofen, meprobamate, naproxen, N,N-diethyl-meta-toluamide (DEET), para-chlorobenzoic acid (pCBA), phenytoin, primidone, sulfamethoxazole, triclosan, trimethoprim, and tris-(2-chloroethyl)-phosphate (TCEP) (R(2) = 0.50-0.83) and the inactivation of three microbial surrogates, including Escherichia coli, MS2, and Bacillus subtilis spores (R(2) = 0.46-0.78). Nine wastewaters were tested in laboratory systems, and eight wastewaters were evaluated at pilot- and full-scale. A predictive model for OH exposure based on ΔUV(254) or ΔTF was also proposed.

  8. The aquatic vascular plant Ruppia maritima as an indicator organism for contaminated sediments

    SciTech Connect

    Tagliabue, M.D.; Thursby, G.B.; Walker, H.A.; Johnston, R.K.

    1995-12-31

    An ongoing estuarine ecological risk assessment case study for the Portsmouth Naval Shipyard in the Great Bay Estuary (New Hampshire, Maine) was the catalyst to continue development a rooted aquatic plant sediment toxicity test. Laboratory studies were conducted to evaluate effects of lead, the primary site contaminant on R. maritima in the Great Bay. Although the aquatic vascular plant Zostra marina comprises up to 46% of the Great Bay subtidal habitat, R. maritima`s much smaller size makes it a more practical laboratory organism. Effects on Ruppia may offer useful insights into potential effects on Zostra or other aquatic vascular plants. Presently rooted vascular plants are not found in Clark Cove located adjacent to a landfill disposal site on the shipyard. The absence of rooted vegetation can be contributed to, physical parameters of the site (turbidity, grain size, texture) or chemical parameters (heavy metal/Pb contamination, redox potential). Exposure of bedded and nonbedded plants occurred over a four day and ten day period using lead sulfate. Concentrations for bedded exposures were as follows, 0.3, 0.5, 0.8, 1.0 simultaneously extracted metal/acid volatile sulfide (SEM/AVS) molar ratios, and 0.1, 1.0, 10.0 and 100.0mg/l Pb for water only exposures. Reduction in cumulative leaf growth was observed for the Clark Cove sediments as well as the spiked sediments as compared to reference sediments.

  9. Effect of soil texture on surfactant-based remediation of hydrophobic organic-contaminated soil.

    PubMed

    Lee, Dal-Heui; Cody, Robert D; Kim, Dong-Ju; Choi, Sangil

    2002-03-01

    Surfactants may be used in remediation of subsoil and aquifer contaminated with hydrophobic compounds. The objectives of this study were to examine the effect of soil texture on hydrophobic organic contaminant (HOC; toluene, or 1,2,4-trichlorobenzene [TCB]) removal from six soils and to evaluate the optimal composition of soil texture for maximum HOC removal using aqueous surfactant solution. Selected surfactants were 4% (vol/vol) sodium diphenyl oxide disulfonate (DOSL) and 4% (wt/vol) sodium lauryl sulfate (LS). Toluene and TCB were selected as the lighter-than-water nonaqueous phase liquid (LNAPL) and denser-than-water nonaqueous phase liquid (DNAPL) model substances, respectively. Soil types used for this study were Ottawa sand and five Iowa soils (Fruitfield, Keomah, Crippin, Webster, and Galvar). The greatest recovery of toluene and TCB in batch tests was 73% and 84%, respectively, which was obtained with DOSL surfactant in Ottawa sand. The toluene removal of 95% in column tests has been achieved in the Ottawa sand and three Iowa soils (Fruitfield, Keomah, Crippin) with DOSL after effluent volume of 3750 ml (about 32 pore volume) passed. TCB removal of 98% in column tests has been achieved in Ottawa sand and three Iowa soils (Fruitfield, Keomah, Crippin) with DOSL after effluent volume of 2500 ml (about 21 pore volume) passed. These results were related with soil texture (clay content 30%), clay mineralogy (kaolinite and smectite), as a function of transported pore volume. PMID:11934118

  10. Experimental investigations of the entrapment and persistence of organic liquid contaminants in the subsurface environment.

    PubMed Central

    Abriola, L M; Bradford, S A

    1998-01-01

    Organic liquids are common polluters of the subsurface environment. Once released, these nonaqueous phase liquids (NAPLs) tend to become entrapped within soils and geologic formations where they may serve as long-term contaminant reservoirs. The interphase mass transfer from such entrapped residuals will ultimately control environmental exposure levels as well as the persistence and/or remedial recovery of these contaminants in the subsurface. This paper summarizes National Institute of Environmental Health Sciences-sponsored research designed to investigate and quantify NAPL entrapment and interphase mass transfer in natural porous media. Results of soil column and batch experiments are presented that highlight research findings over the past several years. These experiments explore dissolution and volatilization of hydrocarbons and chlorinated solvents in sandy porous media. Initial concentration levels and long-term recovery rates are shown to depend on fluid flow rate, soil structure, NAPL composition, and soil wetting characteristics. These observations are explained in the context of conceptual models that describe entrapped NAPL morphology and boundary layer transport. The implications of these laboratory findings on the subsurface persistence and recovery of entrapped NAPLs are discussed. Images Figure 1 Figure 3 Figure 9 PMID:9703497

  11. Effects of metal-contaminated forest soils from the Canadian shield to terrestrial organisms.

    PubMed

    Feisthauer, Natalie C; Stephenson, Gladys L; Princz, Juliska I; Scroggins, Richard P

    2006-03-01

    The effects of elevated metal concentrations in forest soils on terrestrial organisms were investigated by determining the toxicity of six site soils from northern Ontario and Quebec, Canada, using a battery of terrestrial toxicity tests. Soils were collected from three sites on each of two transects established downwind of nickel (Sudbury, ON, Canada) and copper (Rouyn-Noranda, PQ, Canada) smelting operations. Site soils were diluted to determine if toxicity estimates for the most-contaminated site soils could be quantified as a percent of site soil. Rouyn-Noranda soils were toxic following acute exposure (14 d) to plants, but not to invertebrates (7 d for collembola and 14 d for earthworms). However, Rouyn-Noranda soils were toxic to all species following chronic exposure (21, 35, and 63 d for plants, collembola, and earthworms, respectively). The toxicity of the Rouyn-Noranda site soils did not correspond to the gradient of metal concentrations in soil. Metal-contaminated Sudbury soils were toxic to plants but not to invertebrates, following acute exposure. Chronic exposure to Sudbury soils caused adverse effects to plant growth and invertebrate survival and reproduction. The toxicity of Sudbury soils corresponded to the metal concentration gradient, with one exception: The reference soil collected in October was toxic to collembola following acute and chronic exposure. This study evaluated the applicability of the new Environment Canada terrestrial toxicity test methods, developed using agricultural soils, to forest soils and also provided useful data to assess the ecological risk associated with mixtures of metals in soil.

  12. Effect of soil texture on surfactant-based remediation of hydrophobic organic-contaminated soil.

    PubMed

    Lee, Dal-Heui; Cody, Robert D; Kim, Dong-Ju; Choi, Sangil

    2002-03-01

    Surfactants may be used in remediation of subsoil and aquifer contaminated with hydrophobic compounds. The objectives of this study were to examine the effect of soil texture on hydrophobic organic contaminant (HOC; toluene, or 1,2,4-trichlorobenzene [TCB]) removal from six soils and to evaluate the optimal composition of soil texture for maximum HOC removal using aqueous surfactant solution. Selected surfactants were 4% (vol/vol) sodium diphenyl oxide disulfonate (DOSL) and 4% (wt/vol) sodium lauryl sulfate (LS). Toluene and TCB were selected as the lighter-than-water nonaqueous phase liquid (LNAPL) and denser-than-water nonaqueous phase liquid (DNAPL) model substances, respectively. Soil types used for this study were Ottawa sand and five Iowa soils (Fruitfield, Keomah, Crippin, Webster, and Galvar). The greatest recovery of toluene and TCB in batch tests was 73% and 84%, respectively, which was obtained with DOSL surfactant in Ottawa sand. The toluene removal of 95% in column tests has been achieved in the Ottawa sand and three Iowa soils (Fruitfield, Keomah, Crippin) with DOSL after effluent volume of 3750 ml (about 32 pore volume) passed. TCB removal of 98% in column tests has been achieved in Ottawa sand and three Iowa soils (Fruitfield, Keomah, Crippin) with DOSL after effluent volume of 2500 ml (about 21 pore volume) passed. These results were related with soil texture (clay content 30%), clay mineralogy (kaolinite and smectite), as a function of transported pore volume.

  13. Bottom sediment as a source of organic contaminants in Lake Mead, Nevada, USA

    USGS Publications Warehouse

    Alvarez, David A.; Rosen, Michael R.; Perkins, Stephanie D.; Cranor, Walter L.; Schroeder, Vickie L.; Jones-Lepp, Tammy L.

    2012-01-01

    Treated wastewater effluent from Las Vegas, Nevada and surrounding communities' flow through Las Vegas Wash (LVW) into the Lake Mead National Recreational Area at Las Vegas Bay (LVB). Lake sediment is a likely sink for many hydrophobic synthetic organic compounds (SOCs); however, partitioning between the sediment and the overlying water could result in the sediment acting as a secondary contaminant source. Locating the chemical plumes may be important to understanding possible chemical stressors to aquatic organisms. Passive sampling devices (SPMDs and POCIS) were suspended in LVB at depths of 3.0, 4.7, and 6.7 (lake bottom) meters in June of 2008 to determine the vertical distribution of SOCs in the water column. A custom sediment probe was used to also bury the samplers in the sediment at depths of 0–10, 10–20, and 20–30 cm. The greatest number of detections in samplers buried in the sediment was at the 0–10 cm depth. Concentrations of many hydrophobic SOCs were twice as high at the sediment–water interface than in the mid and upper water column. Many SOCs related to wastewater effluents, including fragrances, insect repellants, sun block agents, and phosphate flame retardants, were found at highest concentrations in the middle and upper water column. There was evidence to suggest that the water infiltrated into the sediment had a different chemical composition than the rest of the water column and could be a potential risk exposure to bottom-dwelling aquatic organisms.

  14. Chemical and toxicologic assessment of organic contaminants in surface water using passive samplers

    USGS Publications Warehouse

    Alvarez, D.A.; Cranor, W.L.; Perkins, S.D.; Clark, R.C.; Smith, S.B.

    2008-01-01

    Passive sampling methodologies were used to conduct a chemical and toxicologic assessment of organic contaminants in the surface waters of three geographically distinct agricultural watersheds. A selection of current-use agrochemicals and persistent organic pollutants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides, were targeted using the polar organic chemical integrative sampler (POCIS) and the semipermeable membrane device passive samplers. In addition to the chemical analysis, the Microtox assay for acute toxicity and the yeast estrogen screen (YES) were conducted as potential assessment tools in combination with the passive samplers. During the spring of 2004, the passive samplers were deployed for 29 to 65 d at Leary Weber Ditch, IN; Morgan Creek, MD; and DR2 Drain, WA. Chemical analysis of the sampler extracts identified the agrochemicals predominantly used in those areas, including atrazine, simazine, acetochlor, and metolachlor. Other chemicals identified included deethylatrazine and deisopropylatrazine, trifluralin, fluoranthene, pyrene, cis- and trans-nonachlor, and pentachloroanisole. Screening using Microtox resulted in no acutely toxic samples. POCIS samples screened by the YES assay failed to elicit a positive estrogenic response. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  15. Study of organic contamination induced by outgassing materials. Application to the Laser MégaJoule optics

    NASA Astrophysics Data System (ADS)

    Favrat, O.; Mangote, B.; Tovena-Pécault, I.; Néauport, J.

    2014-02-01

    Organic contamination may decrease the targeted performances of coated surfaces. To study the contamination induced by surrounding materials, a method using a thermal extractor is presented in the first part of this work. Besides its normal operation (analyses of outgassing compounds from a material), this device is used in an original way to contaminate and decontaminate samples. Efficiency of contamination and decontamination protocols are assessed by automated thermal desorption and gas chromatography coupled with mass spectrometry and by secondary ion mass spectrometry coupled with a time of flight mass analyzer. This enables to study the contamination induced by a bulk material outgassing and to take in consideration the possible competition between outgassed species. This method is then applied to investigate contamination of Laser MégaJoule sol-gel coated optics by a retractable sheath. The impact of the temperature on the outgassing of the sheath has been highlighted. Increasing temperature from 30 to 50 °C enables the outgassing of organophosphorous compounds and increases the outgassing of oxygenated compounds and phthalates. Chemical analyses of contaminated optics have highlighted affinities between the sol-gel coating and phthalates and organophosphorous, and low affinities with aromatics and terpens. Finally, samples with increasing levels of contamination have been realized. However a saturation phenomenon is observed at 90 ng cm-2.

  16. Non-target screening analyses of organic contaminants in river systems as a base for monitoring measures

    NASA Astrophysics Data System (ADS)

    Schwarzbauer, J.

    2009-04-01

    Organic contaminants discharged to the aquatic environment exhibit a high diversity with respect to their molecular structures and the resulting physico-chemical properties. The chemical analysis of anthropogenic contamination in river systems is still an important feature, especially with respect to (i) the identification and structure elucidation of novel contaminants, (ii) to the characterisation of their environmental behaviour and (iii) to their risk for natural systems. A huge proportion of riverine contamination is caused by low-molecular weight organic compounds, like pesticides plasticizers, pharmaceuticals, personal care products, technical additives etc. Some of them, like PCB or PAH have already been investigated thoroughly and, consequently, their behaviour in aqueous systems is very well described. Although analyses on organic substances in river water traditionally focused on selected pollutants, in particular on common priority pollutants which are monitored routinely, the occurrence of further contaminants, e.g. pharmaceuticals, personal care products or chelating agents has received increasing attention within the last decade. Accompanied, screening analyses revealing an enormous diversity of low-molecular weight organic contaminants in waste water effluents and river water become more and more noticed. Since many of these substances have been rarely noticed so far, it will be an important task for the future to study their occurrence and fate in natural environments. Further on, it should be a main issue of environmental studies to provide a comprehensive view on the state of pollution of river water, in particular with respect to lipophilic low molecular weight organic contaminants. However, such non-target-screening analyses has been performed only rarely in the past. Hence, we applied extended non-target screening analyses on longitudinal sections of the rivers Rhine, Rur and Lippe (Germany) on the base of GC/MS analyses. The investigations

  17. Structures and spectra of complexes of tetra-tetrazole macrocycle with organic contaminants

    NASA Astrophysics Data System (ADS)

    Teng, Yifei; Du, Jingshan; Xu, Junbo; Teng, Qiwen; Wu, Shi

    2015-06-01

    The binding affinities of the tetra-tetrazole macrocycle to organic contaminants were studied using density function theory (DFT) at B3LYP/6-31G( d, p) level after the basis set superior error (BSSE). The host molecule shows the binding affinity to the guest molecules owing to the formation of the hydrogen bonds. Based on the B3LYP/6-31G( d) optimized geometries, the electronic spectra of the complexes were calculated using INDO/CIS method. The first absorption bands in the electronic spectra of most of the complexes, compared with that of the host, are red-shifted. The chemical shifts of the carbon atoms with sp 3 hybridization in the host, calculated at B3LYP/6-31G( d) level, are basically shifted upwards. The complex formed by the host and acrolein exhibits the aromaticity although the host shows the anti-aromaticity.

  18. Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams

    USGS Publications Warehouse

    Buxton, Herbert T.; Kolpin, Dana W.

    2002-01-01

    A recent study by the Toxic Substances Hydrology Program of the U.S. Geological Survey (USGS) shows that a broad range of chemicals found in residential, industrial, and agricultural wastewaters commonly occurs in mixtures at low concentrations downstream from areas of intense urbanization and animal production. The chemicals include human and veterinary drugs (including antibiotics), natural and synthetic hormones, detergent metabolites, plasticizers, insecticides, and fire retardants. One or more of these chemicals were found in 80 percent of the streams sampled. Half of the streams contained 7 or more of these chemicals, and about one-third of the streams contained 10 or more of these chemicals. This study is the first national-scale examination of these organic wastewater contaminants in streams and supports the USGS mission to assess the quantity and quality of the Nation's water resources. A more complete analysis of these and other emerging water-quality issues is ongoing.

  19. Effect of flagellates on free-living bacterial abundance in an organically contaminated aquifer.

    PubMed

    Kinner, N E; Harvey, R W; Kazmierkiewicz-Tabaka, M

    1997-07-01

    Little is known about the role of protists in the saturated subsurface. Porous media microcosms, containing bacteria and protists, were used to determine whether flagellates from an organically contaminated aquifer could substantively affect the number of free-living bacteria (FLB). When flagellates were present, the 3-40% maximum breakthrough of fluorescently labelled FLB injected into the microcosms was much lower than the 60-130% observed for killed controls. Grazing and clearance rates (3-27 FLB flag-1 h-1 and 12-23 nl flag-1 h-1, respectively) calculated from the data were in the range reported for flagellates in other aqueous environments. The data provide evidence that flagellate bacterivory is an important control on groundwater FLB populations.

  20. Permeable sorptive walls for treatment of hydrophobic organic contaminant plumes in groundwater

    SciTech Connect

    Grathwohl, P.; Peschik, G.

    1997-12-31

    Highly hydrophobic contaminants are easily adsorbed from aqueous solutions. Since for many of these compounds sorption increases with increasing organic carbon content natural materials such as bituminous shales and coals may be used in permeable sorptive walls. This, however, only applies if sorption is at equilibrium, which may not always be the case in groundwater treatment using a funnel-and-gate system. In contrast to the natural solids, granular activated carbons (GACs) have very high sorption capacities and reasonably fast sorption kinetics. The laboratory results show that application of GACs (e.g. F100) is economically feasible for in situ removal of polycyclic aromatic hydrocarbons (PAH) from groundwater at a former manufactured gas plant site (MGP). For less sorbing compounds (such as benzene, toluene, xylenes) a combination of adsorption and biodegradation is necessary (i.e. sorptive + reactive treatment).

  1. A high throughout semi-quantification method for screening organic contaminants in river sediments.

    PubMed

    Bu, Qingwei; Wang, Donghong; Liu, Xin; Wang, Zijian

    2014-10-01

    A high throughout semi-quantification method for screening nearly 900 organic contaminants (OCs) in river sediments has been developed. For most OCs tested, concentrations calculated from the proposed semi-quantification method deviated from actual values by a factor of 4. The overall recovery tests indicated that most OCs can be successfully extracted from sediments with recovery rates from 84.1 to 128.6%. To demonstrate the effectiveness of our method towards OC quantification, we screened OCs from sediments collected from the Haihe River basin. Seventy unregulated OCs (including pesticides, flame retardants, PPCPs, etc.) were identified and quantified at concentrations up to 2600 ng/g from 24 sediment samples. From these results, it is confirmed that the developed method is a useful way to fulfill a comprehensive analysis of OCs in sediments and would be valuable for the identification and prioritization of priority pollutants in watershed management.

  2. Effect of flagellates on free-living bacterial abundance in an organically contaminated aquifer

    USGS Publications Warehouse

    Kinner, N.E.; Harvey, R.W.; Kazmierkiewicz-Tabaka, M.

    1997-01-01

    Little is known about the role of protists in the saturated subsurface. Porous media microcosms containing bacteria and protists, were used to determine whether flagellates from an organically contaminated aquifer could substantively affect the number of free- living bacteria (FLB). When flagellates were present, the 3-40% maximum breakthrough of fluorescent y labelled FLB injected into the microcosms was much lower than the 60-130% observed for killed controls Grazing and clearance rates (3-27 FLB flag-1 h-1 and 12-23 nI flag-1 h-1, respectively) calculated from the data were in the range reported for flagellates in other aqueous environments. The data provide evidence that flagellate bacterivory is an important control on groundwater FLB populations.

  3. Survey of organic wastewater contaminants in biosolids destined for land application

    USGS Publications Warehouse

    Kinney, C.A.; Furlong, E.T.; Zaugg, S.D.; Burkhardt, M.R.; Werner, S.L.; Cahill, J.D.; Jorgensen, G.R.

    2006-01-01

    In this study, the presence, composition, and concentrations of organic wastewater contaminants (OWCs) were determined in solid materials produced during wastewater treatment. This study was undertaken to evaluate the potential of these solids, collectively referred to as biosolids, as a source of OWCs to soil and water in contact with soil. Nine different biosolid products, produced by municipal wastewater treatment plants in seven different states, were analyzed for 87 different OWCs. Fifty-five of the OWCs were detected in at least one biosolid product. The 87 different OWCs represent a diverse cross section of emerging organic contaminants that enter wastewater treatment plants and may be discharged without being completely metabolized or degraded. A minimum of 30 and a maximum of 45 OWCs were detected in any one biosolid. The biosolids used in this study are produced by several production methods, and the plants they originate from have differing population demographics, yet the percent composition of total OWC content, and of the most common OWCs, typically did not vary greatly between the biosolids tested. The summed OWC content ranged from 64 to 1811 mg/kg dry weight. Six biosolids were collected twice, 3-18 months apart, and the total OWC content of each biosolid varied by less than a factor of 2. These results indicate that the biosolids investigated in this study have OWC compositions and concentrations that are more similar than different and that biosolids are highly enriched in OWCs (as mass-normalized concentrations) when compared to effluents or effluent-impacted water. These results demonstrate the need to better describe the composition and fate of OWCs in biosolids since about 50% of biosolids are land applied and thus become a potentially ubiquitous nonpoint source of OWCs into the environment. ?? 2006 American Chemical Society.

  4. The aquatic vascular plant Ruppia maritima as an indicator organisms for contaminated sediments

    SciTech Connect

    Tagliabue, M.D.; Thursby, G.B.; Walker, H.A.; Johnston, R.K.

    1994-12-31

    An ongoing estuarine ecological risk assessment case study for the Portsmouth Naval Shipyard in the Great Bay (Kittery, ME, Portsmouth, NH) has been the catalyst for continued methods development with a rooted aquatic plant for a sediment toxicity test. A test using the aquatic vascular plant Ruppia maritima would be similar in it`s utility to the Algal (Champia parvula) Reproduction Test, an accepted, short term test (US EPA Short term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms). Laboratory studies were conducted to evaluate effects of lead, the primary site contaminant on R. maritima in the Great Bay. Morphology and life cycle of R. maritima are similar to that of the aquatic vascular plant Zostra marina which comprises up to 46% of the Great Bay habitat (Short 1992). R. maritima`s reduced size makes it a practical laboratory organism and Ruppia`s effects may offer useful insights into potential effects on Zostra or other aquatic vascular plants. Presently rooted vascular plants are not found in the site of concern (Clark Cove). This can be contributed to either of two factors; the physical parameters of the site, i.e., a depositional zone or the chemical parameters, i.e., metals contamination, specifically lead. Exposure of bedded and nonbedded plants occurred over a four day and ten day period using lead sulfate. Concentrations for bedded exposures were as follows, 0.3, 0.5, 0.8, 1.0 simultaneously extracted metal/acid volatile sulfide (SEM/AVS) molar ratios, and 0.1, 1.0, 10.0 and 100.0mg/l Pb for water only exposures. Some reduction in cumulative leaf growth was observed in the site samples as well as the spiked samples as compared to site controls. Results of this study and associated research which focuses on the further development of the Ruppia test methods will be presented.

  5. A contribution to reduce sampling variability in the evaluation of deoxynivalenol contamination of organic wheat grain.

    PubMed

    Hallier, Arnaud; Celette, Florian; Coutarel, Julie; David, Christophe

    2013-01-01

    Fusarium head blight caused by different varieties of Fusarium species is one of the major serious worldwide diseases found in wheat production. It is therefore important to be able to quantify the deoxynivalenol concentration in wheat. Unfortunately, in mycotoxin quantification, due to the uneven distribution of mycotoxins within the initial lot, it is difficult, or even impossible, to obtain a truly representative analytical sample. In previous work we showed that the sampling step most responsible for variability was grain sampling. In this paper, it is more particularly the step scaling down from a laboratory sample of some kilograms to an analytical sample of a few grams that is investigated. The naturally contaminated wheat lot was obtained from an organic field located in the southeast of France (Rhône-Alpes) from the year 2008-2009 cropping season. The deoxynivalenol level was found to be 50.6 ± 2.3 ng g⁻¹. Deoxynivalenol was extracted with a acetonitrile-water mix and quantified by gas chromatography-electron capture detection (GC-ECD). Three different grain sampling techniques were tested to obtain analytical samples: a technique based on manually homogenisation and division, a second technique based on the use of a rotating shaker and a third on the use of compressed air. Both the rotating shaker and the compressed air techniques enabled a homogeneous laboratory sample to be obtained, from which representative analytical samples could be taken. Moreover, the techniques did away with many repetitions and grinding. This study, therefore, contributes to sampling variability reduction in the evaluation of deoxynivalenol contamination of organic wheat grain, and then, at a reasonable cost.

  6. Non-invasive monitoring of the degradation of organic contaminants: A laboratory investigation

    NASA Astrophysics Data System (ADS)

    Fernandez, Perrine M.; Bloem, Esther; Philippe, Romain; Binley, Andrew; French, Helen K.

    2016-04-01

    Degradation of organic chemicals under various fluid saturation conditions is a process highly relevant to the protection of groundwater quality. Redox potential drives the degradation of organic compounds; its variation affects the water chemistry, gas release and also the geo-electrical signature. This study explores how non-invasive measurements sensitive to geo-electrical properties provides quantitative information about the in-situ redox conditions. Our laboratory experiment focuses on the degradation of de-icing chemicals commonly used, for example, in Norwegian airports. The experiment was conducted in a number of (1.0x0.5x0.4 m) sand boxes. Two ends of each box was contaminated with propylene glycol, an aircraft deicing fluid. Each source was placed near the water table under static hydraulic conditions. At one side of the tank, a conductor linking the contamination zone, near the water table and the unsaturated zone with a low water content, was placed to improve the degradation by facilitating the electron exchange. At the other side, degradation occurred under natural conditions. Each box was equipped with 288 electrodes, distributed on six faces to perform 3D resistivity measurements. In addition, self-potential measurements were taken from electrodes on the sand surface. Four observation wells were installed above and below the water table to provide more information on the degradation processes. Moreover, measurements of carbon dioxide on the surface were performed as higher concentrations were expected where the pollutant degraded. We would like to present and discuss a selection of the preliminary results of 3D electrical resistivity and self-potential techniques from our laboratory setup.

  7. 3D resistivity method to monitor degradation of an organic contaminant in sand boxes

    NASA Astrophysics Data System (ADS)

    Fernandez, P. M.; Bloem, E.; Philippe, R.; French, H. K.

    2015-12-01

    Degradation of organic chemicals under various saturation conditions is a process highly relevant to protect groundwater. The redox potential drives the degradation of organic compounds. Its variation affects the water chemistry, gas release and responses of the geo-electrical signature. This study explores how non-invasive measurements sensitive to geo-electrical properties provides quantitative information about the in-situ redox situation. During this presentation, the preliminary results of a laboratory experiment to study the degradation of deicing chemicals with 3D resistivity and self-potential techniques, water samples will be shown. The experiment consists of sand boxes (1.0x0.5x0.4 m) to which both sides of each box is contaminated with propylene glycol, an aircraft deicing fluid, commonly used in Norwegian airports. Each source is placed near the water table with static conditions. At one side a conductor is placed, linking the contamination zone at the water table and the unsaturated zone with a low water content, to improve the degradation by facilitating the electron exchange. At the other side, degradation occurs under natural conditions. Each box is equipped with 288 electrodes, distributed on six faces to perform 3D resistivity measurements. In addition to the resistivity, self-potential measurements are taken from the sand surface. Six water wells are installed above and below the water table to provide more information on the degradation processes. Moreover, measurements of carbon dioxide on the surface are performed as higher concentrations are expected where the pollutant is degraded.

  8. Phylogenetic analysis of bacterial community composition in sediments with organic contaminants from the Jiaojiang estuary in China.

    PubMed

    Jiang, Ran; Wang, Jian-Xin; Huang, Bei; Yu, Kai-Cheng; Zhang, Pan; Zheng, Jun-Wei; Liu, Xue-Zhu

    2016-08-15

    The aim of this study was to investigate the bacterial community composition, the concentration of organic contaminants, and their relationship in the sediments of Jiaojiang estuary. Sediments were collected from seven stations and the environmental parameters were analyzed. The results showed that the site closest to the chemical industry zone was the most polluted. Bacterial communities were determined using 16S rRNA clone libraries and phylogenetic analysis. These results revealed that there were 13 known bacterial phyla in the sediments and that Proteobacteria were the dominant group. Using these data, we assessed the correlation between bacterial communities and organic contaminants using cluster, multidimensional scaling, and redundancy analyses. These showed that there was no simple relationship between organic contaminants and bacterial community diversity in the sediments, but polycyclic aromatic hydrocarbons were more influential than the other pollutants and negatively affected Chloroflexi. PMID:27234368

  9. Use of on-site high performance liquid chromatography to evaluate the magnitude and extent of organic contaminants in aquifers

    USGS Publications Warehouse

    Goerlitz, D.F.; Franks, B.J.

    1989-01-01

    Appraisal of ground water contaminated by organic substances raises problems of difficult sample collection and timely chemical analysis. High-performance liquid chromatography was evaluated for on-site determination of specific organic contaminants in ground water samples and was used at three study sites. Organic solutes were determined directly in water samples, with little or no preparation, and usually in less than an hour after collection. This information improved sampling efficiency and was useful in screening for subsequent laboratory analysis. On two occasions, on-site analysis revealed that samples were undergoing rapid change, with major solutes being upgraded and alteration products being formed. In addition to sample stability, this technique proved valuable for monitoring other sampling factors such as compositional changes with respect to pumping, filtration, and cross contamination. -Authors

  10. Performance of isotope ratio infrared spectroscopy (IRIS) for analyzing waters containing organic contaminants: Problems and solutions (Invited)

    NASA Astrophysics Data System (ADS)

    West, A. G.; Goldsmith, G. R.; Dawson, T. E.

    2010-12-01

    The development of isotope ratio infrared spectroscopy (IRIS) for simultaneous δ2H and δ18O analysis of liquid water samples shows much potential for affordable, simple and potentially portable isotopic analyses. IRIS has been shown to be comparable in precision and accuracy to isotope ratio mass spectrometry (IRMS) when analyzing pure water samples. However, recent studies have shown that organic contaminants in analyzed water samples may interfere with the spectroscopy leading to errors of considerable magnitude in the reported stable isotope data. Many environmental, biological and forensic studies require analyses of water containing organic contaminants in some form, yet our current methods of removing organic contaminants prior to analysis appear inadequate for IRIS. Treated plant water extracts analyzed by IRIS showed deviations as large as 35‰ (δ2H) and 11.8‰ (δ18O) from the IRMS value, indicating that trace amounts of contaminants were sufficient to disrupt IRIS analyses. However, not all organic contaminants negatively influence IRIS. For such samples, IRIS presents a labour saving method relative to IRMS. Prior to widespread use in the environmental, biological and forensic sciences, a means of obtaining reliable data from IRIS needs to be demonstrated. One approach is to use instrument-based software to flag potentially problematic spectra and output a corrected isotope value based on analysis of the spectra. We evaluate this approach on two IRIS systems and discuss the way forward for ensuring accurate stable isotope data using IRIS.

  11. Diagenetic fate of organic contaminants on the Palos Verdes Shelf, California

    USGS Publications Warehouse

    Eganhouse, R.P.; Pontolillo, J.; Leiker, T.J.

    2000-01-01

    Municipal wastes discharged through deepwater submarine outfalls since 1937 have contaminated sediments of the Palos Verdes Shelf. A site approximately 6-8 km downcurrent from the outfall system was chosen for a study of the diagenetic fate of organic contaminants in the waste-impacted sediments. Concentrations of three classes of hydrophobic organic contaminants (DDT + metabolites, polychlorinated biphenyls (PCBs), and the long-chain alkylbenzenes) were determined in sediment cores collected at the study site in 1981 and 1992. Differences between the composition of effluent from the major source of DDT (Montrose Chemical) and that found in sediments suggests that parent DDT was transformed by hydrolytic dehydrochlorination during the earliest stages of diagenesis. As a result, p,p'-DDE is the dominant DDT metabolite found in shelf sediments, comprising 60-70% of ??DDT. The p,p-DDE/p,p'-DDMU concentration ratio decreases with increasing sub-bottom depth in sediment cores, indicating that reductive dechlorination of p,p'-DDE is occurring. Approximately 9-23% of the DDE inventory in the sediments may have been converted to DDMU since DDT discharges began ca. 1953. At most, this is less than half of the decline in p,p'-DDE inventory that has been observed at the study site for the period 1981-1995. Most of the observed decrease is attributable to remobilization by processes such as sediment mixing coupled to resuspension, contaminant desorption, and current advection. Existing field data suggest that the in situ rate of DDE transformation is 102-103 times slower than rates determined in recent laboratory microcosm experiments (Quensen, J.F., Mueller, S.A., Jain, M.K., Tiedje, J.M., 1998. Reductive dechlorination of DDE to DDMU in marine sediment microcosms. Science, 280, 722-724.). This explains why the DDT composition (i.e. o,p'-, p,p'-isomers of DDE, DDD, DDT) of sediments from this site have not changed significantly since at least 1972. Congener-specific PCB

  12. Monitoring priority substances, other organic contaminants and heavy metals in a volcanic aquifer from different sources and hydrological processes.

    PubMed

    Estevez, Esmeralda; Cabrera, María del Carmen; Fernández-Vera, Juan Ramón; Molina-Díaz, Antonio; Robles-Molina, José; Palacios-Díaz, María del Pino

    2016-05-01

    Irrigation with reclaimed water (R) is necessary to guarantee the sustainability of semi-arid areas. Results obtained during a two years monitoring network (2009-2011) in Gran Canaria are presented, including the analysis of chemical parameters, N and S isotopes, priority substances (2008/105/EC, 2013/39/EU), other organic contaminants and heavy metals in groundwater and R used to irrigate a golf course. The aims of this work are to evaluate the contamination in a volcanic aquifer, relate the presence of organic contaminants and heavy metals with the hydrogeochemistry and identify pollution sources in the area. No priority substance exceeded the EU thresholds for surface water, although seventeen were detected in R. The most frequent compounds were hexachlorobenzene, chlorpyrifos ethyl, fluorene, phenanthrene and pyrene. These compounds were detected at low concentration, except chlorpyrifos. Chlorpyrifos ethyl, terbuthylazine, diuron, terbutryn, procymidone, atrazine and propazine exceeded the European threshold concentration for pesticides in groundwater (100ngL(-1)). Therefore, the priority substances chlorpyrifos ethyl and diuron must be included in monitoring studies. The priority pesticides chlorfenvinphos and diazinon were always detected in R but rarely in groundwater. Besides, the existence of contaminants not related to the current R irrigation has been identified. Absence of environmental problems related to heavy metals can be expected. The relationship among contaminant presence, hydrogeochemistry, including the stable isotopic prints of δ(18)O, δ(15)N and δ(34)S and preferential recharge paths has been described. The coastal well shows high values of EC, nitrate, a variable chemistry, and 50% of organic contaminants detected above 100ngL(-1). The well located in the recharge area presents a stable hydrochemistry, the lowest value of δ(15)N and the lowest contaminants occurrence. The area is an example of a complex volcanic media with several

  13. Monitoring priority substances, other organic contaminants and heavy metals in a volcanic aquifer from different sources and hydrological processes.

    PubMed

    Estevez, Esmeralda; Cabrera, María del Carmen; Fernández-Vera, Juan Ramón; Molina-Díaz, Antonio; Robles-Molina, José; Palacios-Díaz, María del Pino

    2016-05-01

    Irrigation with reclaimed water (R) is necessary to guarantee the sustainability of semi-arid areas. Results obtained during a two years monitoring network (2009-2011) in Gran Canaria are presented, including the analysis of chemical parameters, N and S isotopes, priority substances (2008/105/EC, 2013/39/EU), other organic contaminants and heavy metals in groundwater and R used to irrigate a golf course. The aims of this work are to evaluate the contamination in a volcanic aquifer, relate the presence of organic contaminants and heavy metals with the hydrogeochemistry and identify pollution sources in the area. No priority substance exceeded the EU thresholds for surface water, although seventeen were detected in R. The most frequent compounds were hexachlorobenzene, chlorpyrifos ethyl, fluorene, phenanthrene and pyrene. These compounds were detected at low concentration, except chlorpyrifos. Chlorpyrifos ethyl, terbuthylazine, diuron, terbutryn, procymidone, atrazine and propazine exceeded the European threshold concentration for pesticides in groundwater (100ngL(-1)). Therefore, the priority substances chlorpyrifos ethyl and diuron must be included in monitoring studies. The priority pesticides chlorfenvinphos and diazinon were always detected in R but rarely in groundwater. Besides, the existence of contaminants not related to the current R irrigation has been identified. Absence of environmental problems related to heavy metals can be expected. The relationship among contaminant presence, hydrogeochemistry, including the stable isotopic prints of δ(18)O, δ(15)N and δ(34)S and preferential recharge paths has been described. The coastal well shows high values of EC, nitrate, a variable chemistry, and 50% of organic contaminants detected above 100ngL(-1). The well located in the recharge area presents a stable hydrochemistry, the lowest value of δ(15)N and the lowest contaminants occurrence. The area is an example of a complex volcanic media with several

  14. Campylobacter contamination and the relative risk of illness from organic broiler meat in comparison with conventional broiler meat.

    PubMed

    Rosenquist, Hanne; Boysen, Louise; Krogh, Anne Louise; Jensen, Annette Nygaard; Nauta, Maarten

    2013-04-01

    Danish organic broiler meat, represented by carcasses sampled at the end of processing after chilling, was more frequently contaminated with thermotolerant Campylobacter spp. than conventional broiler carcasses; the yearly mean prevalence being 54.2% (CI: 40.9-67.5) for organic and 19.7% (CI: 14.8-24.7) for conventional carcasses. Campylobacter jejuni was the most frequently isolated species. The difference in prevalence was obvious in all quarters of the year. Contamination of organic and conventional broiler carcasses was more likely to occur in the warmer summer months, in this case in the third quarter, as also documented for conventional broiler flocks. When contaminated, the mean concentration of Campylobacter on neck skin samples of organic and conventional carcasses was not significantly different (P=0.428); 2.0±0.65 log 10 cfu/g and 2.1±0.93 log 10 cfu/g, respectively. Assessing the relative risk of becoming ill following exposure to Campylobacter on conventional or organic broiler meat indicated that the risk per serving from organic carcasses was 1.7 times higher than that of conventional carcasses. The higher risk of illness from organic broiler carcasses compared with conventional broiler carcasses emphasizes the importance of implementing control measures in organic broiler production.

  15. Comparison of the removal of hydrophobic trace organic contaminants by forward osmosis and reverse osmosis.

    PubMed

    Xie, Ming; Nghiem, Long D; Price, William E; Elimelech, Menachem

    2012-05-15

    We compared the rejection behaviours of three hydrophobic trace organic contaminants, bisphenol A, triclosan and diclofenac, in forward osmosis (FO) and reverse osmosis (RO). Using erythritol, xylose and glucose as inert reference organic solutes and the membrane pore transport model, the mean effective pore size of a commercial cellulose-based FO membrane was estimated to be 0.74 nm. When NaCl was used as the draw solute, at the same water permeate flux of 5.4 L/m(2) h (or 1.5 μm/s), the adsorption of all three compounds to the membrane in the FO mode was consistently lower than that in the RO mode. Rejection of bisphenol A and diclofenac were higher in the FO mode compared to that in the RO mode. Because the molecular width of triclosan was larger than the estimated mean effective membrane pore size, triclosan was completely rejected by the membrane and negligent difference between the FO and RO modes could be observed. The difference in the separation behaviour of these hydrophobic trace organics in the FO (using NaCl the draw solute) and RO modes could be explained by the phenomenon of retarded forward diffusion of solutes. The reverse salt flux of NaCl hinders the pore diffusion and subsequent adsorption of the trace organic compounds within the membrane. The retarded forward diffusion effect was not observed when MgSO(4) and glucose were used as the draw solutes. The reverse flux of both MgSO(4) and glucose was negligible and thus both adsorption and rejection of BPA in the FO mode were identical to those in the RO mode.

  16. Organic contaminants in sewage sludge (biosolids) and their significance for agricultural recycling.

    PubMed

    Smith, S R

    2009-10-13

    Organic chemicals discharged in urban wastewater from industrial and domestic sources, or those entering through atmospheric deposition onto paved areas via surface run-off, are predominantly lipophilic in nature and therefore become concentrated in sewage sludge, with potential implications for the agricultural use of sludge as a soil improver. Biodegradation occurs to varying degrees during wastewater and sludge treatment processes. However, residues will probably still be present in the resulting sludge and can vary from trace values of several micrograms per kilogram up to approximately 1 per cent in the dry solids for certain bulk chemicals, such as linear alkylbenzene sulphonate, which is widely used as a surfactant in detergent formulations. However, the review of the scientific literature on the potential environmental and health impacts of organic contaminants (OCs) in sludge indicates that the presence of a compound in sludge, or of seemingly large amounts of certain compounds used in bulk volumes domestically and by industry, does not necessarily constitute a hazard when the material is recycled to farmland. Furthermore, the chemical quality of sludge is continually improving and concentrations of potentially harmful and persistent organic compounds have declined to background values. Thus, recycling sewage sludge on farmland is not constrained by concentrations of OCs found in contemporary sewage sludges. A number of issues, while unlikely to be significant for agricultural utilization, require further investigation and include: (i) the impacts of chlorinated paraffins on the food chain and human health, (ii) the risk assessment of the plasticizer di(2-ethylhexyl)phthalate, a bulk chemical present in large amounts in sludge, (iii) the microbiological risk assessment of antibiotic-resistant micro-organisms in sewage sludge and sludge-amended agricultural soil, and (iv) the potential significance of personal-care products (e.g. triclosan), pharmaceuticals

  17. Caged mussels and semipermeable membrane devices as indicators of organic contaminant uptake in Dorchester and Duxbury Bays, Massachusetts

    SciTech Connect

    Peven, C.S.; Uhler, A.D.; Querzoli, F.J.

    1996-02-01

    An experiment to measure organic contaminant depuration by the blue mussel (Mytilus edulis) was carried out by transplanting mussels in stainless steel cages from a known contaminated site in Dorchester Bay, Massachusetts to a documented clean site in Duxbury Bay, Massachusetts approximately 30 nmi south of the original collection site. A parallel contaminant uptake experiment was performed in which mussels from Duxbury Bay were collected and deployed in similar cages in Dorchester Bay. The bivalves were collected from each transplant site at set intervals over a period of 95 days to monitor the rates and selectivity of depuration and uptake, respectively, of polynuclear atomic hydrocarbons (PAH), polychlorinated biphenyls (PCB), and chlorinated pesticides. In a related study, semipermeable membrane devices (SPMD: polyethylene bags) containing the lipid material triolein were deployed in Dorchester Bay and collected at the same frequency as the caged mussels to evaluate their effectiveness as models for estimating bioconcentration of target organic contaminants. At the Duxbury site, results suggest that the caged mussels depurated contaminants within 68 days to levels found in native animals at the site. At the Dorchester site, bivalves concentrated the contaminants to a level similar to the native M. edulis. PCB and DDT uptake rates were found to be similar between caged mussels and SPMDs; PAH uptake by the SPMDs was initially lower than by transplanted bivalves. PCB and PAH assemblages were noticeably different between bivalves and SPMDs deployed at the same site.

  18. EVALUATING MONITORED NATURAL ATTENUATION FOR RADIONUCLIDE & ORGANIC CONTAMINATION IN GROUNDWATER (SALT LAKE CITY, UT)

    EPA Science Inventory

    Monitored Natural Attenuation (MNA) for radionuclides and inorganic contaminants is dependent on naturally occurring processes in the subsurface that act without human intervention to reduce the mass, toxicity, mobility, volume or concentration of contaminants. EPA is developing ...

  19. Graphene nanosheets and graphite oxide as promising adsorbents for removal of organic contaminants from aqueous solution.

    PubMed

    Ji, Liangliang; Chen, Wei; Xu, Zhaoyi; Zheng, Shourong; Zhu, Dongqiang

    2013-01-01

    Graphenes are an emerging class of carbon nanomaterials whose adsorption properties toward organic compounds have not been well understood. In the present study, graphene nanosheets were prepared by reoxidation and abrupt heating of graphite oxide, which was prepared by sequential chemical oxidation of commercial nonporous graphite powder. Adsorption properties of three aromatic compounds (naphthalene, 2-naphthol, and 1-naphthylamine) and one pharmaceutical compound (tylosin) on graphene nanosheets and graphite oxide were examined to explore the potential of these two adsorbents for the removal of organic contaminants from aqueous solutions. Compared with the literature data of adsorption on carbon nanotubes, adsorption of bulky, flexible tylosin on graphene nanosheets exhibited markedly faster adsorption kinetics, which can be attributed to their opened-up layer structure. Graphene nanosheets and graphite oxide showed similar sequences of adsorption affinity: 1-naphthylamine > 2-naphthol > tylosin > naphthalene (with much larger differences observed on graphite oxide). It was proposed that the strong adsorption of the three aromatic compounds was mainly due to π-π electron donor-acceptor interactions with the graphitic surfaces of adsorbents. Additionally, Lewis acid-base interaction was likely an important factor contributing to the strong adsorption of 1-naphthylamine and tylosin, especially for the O-functionality-abundant graphite oxide. After being normalized on the basis of adsorbent surface area, adsorption affinities of all four tested adsorbates on graphene nanosheets were very close to those on nonporous graphite powder, reflecting complete accessibility of the adsorbent surface area in adsorption.

  20. Activated carbon prepared from coffee pulp: potential adsorbent of organic contaminants in aqueous solution.

    PubMed

    Gonçalves, Maraisa; Guerreiro, Mário César; Ramos, Paulize Honorato; de Oliveira, Luiz Carlos Alves; Sapag, Karim

    2013-01-01

    The processing of coffee beans generates large amounts of solid and liquid residues. The solid residues (pulp, husk and parchment) represent a serious environmental problem and do not have an adequate disposal mechanism. In this work, activated carbons (ACs) for adsorption of organic compounds were prepared from coffee pulp by controlled temperature at different pulp/Na2HPO4 ratios (4:1, 2:1, 5:4 and 1:1). The N2 adsorption/desorption isotherms showed ACs with high quantities of mesopores and micropores and specific surface areas of 140, 150, 450 and 440 m(2)g(-1) for AC 4:1, AC 2:1, AC 5:4 and AC 1:1, respectively. The prepared material AC 5:4 showed a higher removal capacity of the organic contaminants methylene blue (MB), direct red (DR) and phenol than did a Merck AC. The maximum capacities for this AC are approximately 150, 120 and 120 mg g(-1) for MB, DR and phenol, respectively. Thus, a good adsorbent was obtained from coffee pulp, an abundant Brazilian residue.

  1. Effect of colloids on the occurrence, distribution and photolysis of emerging organic contaminants in wastewaters.

    PubMed

    Yan, Caixia; Nie, Minghua; Yang, Yi; Zhou, Junliang; Liu, Min; Baalousha, Mohammed; Lead, Jamie R

    2015-12-15

    The effect of colloids on the occurrence, phase distribution and photolysis of twenty-seven emerging organic contaminants (EOCs) was studied in domestic and livestock wastewaters (DW and LW), respectively. Filtered water (<1 μm) was separated into permeate (<1 kDa) and retentate (1 kDa-1 μm) by cross flow ultrafiltration. Results indicated that total concentration of EOCs ranged from 1220 ng L(-1) in permeate of DW to 5065 ng L(-1) in retentate of LW. The average EOC fraction associated with colloids was 13.5% and 14.4% in DW and LW. Most of the EOCs exhibited pseudo-first-order degradation kinetics in all water samples. Control experiments using glass and quartz reactors showed that UV light was more effective on the photolysis of most EOCs. The EOCs photolysis in the three fractions of DW and LW could be accelerated or inhibited compared to ultrapure water with the enhancement factor ranging from -0.94 to 7.33. The impact of colloids on the photolysis of EOCs depended on the compound and the source of water. The photolysis of most EOCs in permeates and filtrates was generally accelerated, while inhibited in the retentates, which could be attributed to the relatively high dissolved organic carbon contents in retentates.

  2. Photosensitizing and Inhibitory Effects of Ozonated Dissolved Organic Matter on Triplet-Induced Contaminant Transformation.

    PubMed

    Wenk, Jannis; Aeschbacher, Michael; Sander, Michael; von Gunten, Urs; Canonica, Silvio

    2015-07-21

    Dissolved organic matter (DOM) is both a promoter and an inhibitor of triplet-induced organic contaminant oxidation. This dual role was systematically investigated through photochemical experiments with three types of DOM of terrestrial and aquatic origins that were preoxidized to varying extents by ozonation. The inhibitory effect of DOM was assessed by determining the 4-carboxybenzophenone photosensitized transformation rate constants of two sulfonamide antibiotics (sulfamethoxazole and sulfadiazine) in the presence of untreated or preoxidized DOM. The inhibitory effect decreased with the increasing extent of DOM preoxidation, and it was correlated to the loss of phenolic antioxidant moieties, as quantified electrochemically, and to the loss of DOM ultraviolet absorbance. The triplet photosensitizing ability of preoxidized DOM was determined using the conversion of the probe compound 2,4,6-trimethylphenol (TMP), which is unaffected by DOM inhibition effects. The DOM photosensitized transformation rate constants of TMP decreased with increasing DOM preoxidation and were correlated to the concomitant loss of chromophores (i.e., photosensitizing moieties). The combined effects of DOM preoxidation on the inhibiting and photosensitizing properties were assessed by phototransformation experiments of the sulfonamides in DOM-containing solutions. At low extents of DOM preoxidation, the sulfonamide phototransformation rate constants remained either unchanged or slightly increased, indicating that the removal of antioxidant moieties had larger effects than the loss of photosensitizing moieties. At higher extents of DOM preoxidation, transformation rates declined, mainly reflecting the destruction of photosensitizing moieties. PMID:26091366

  3. Development in Waste Volume Reduction Technologies for Highly Contaminated Organic Radioactive Compounds

    SciTech Connect

    AKAI, Yoshie; OHMURA, Hisao; FUJIE, Makoto; MONIWA, Shinobu; SEKI, Shuji; YOTSUYANAGI, Tadasu; EBATA, Masaaki; TAKAGI, Junichi

    2006-07-01

    In nuclear facilities, there is highly contaminated organic radioactive waste such as ion exchange resins for water purification in nuclear power plants. In the future, it is desired that this waste be decomposed to reduce the volume and to become stable. Toshiba has developed a waste treatment system using supercritical water. Furthermore, the new demineralization system without using ion exchange resin has been examined. By this new system, it is possible to reduce the volume of ion exchange resin waste. First, supercritical water was applied to the decomposition of ion exchange resin. The supercritical water whose temperature and pressure exceed 647 K and 22 MPa is an excellent solvent for organic compound decomposition, since oxygen and organic compounds can exist in a single homogeneous fluid phase. Organic compounds can be rapidly and completely decomposed using supercritical water. Almost all the reactants can be kept in the water during organic compound decomposition. Therefore, applying supercritical water to treat organic radioactive waste is an attractive proposition. Actual plant-size apparatus was constructed with a treatment capacity of 1 kg of ion exchange resin per hour. The test revealed that more than 99.9% of the ion exchange resin was decomposed at 723 K and 30 MPa. By this system, ion exchange resin decomposes rapidly and completely, and the volume of ion exchange resin waste can be largely reduced. Secondly, the new demineralization system without using ion exchange resin is described. The new demineralization system consists of a filter and a demineralization cell. A metal mesh filter is adopted to remove crud, and the demineralization cell removes ionic impurities. In this system, it is important whether demineralization can take place at high temperature. Thus, this report describes the test results of the new demineralization process. This demineralization cell consists of an anode, a cathode, and a membrane made of inorganic material. The

  4. Potential contamination of shipboard air samples by diffusive emissions of PCBs and other organic pollutants: implications and solutions.

    PubMed

    Lohmann, Rainer; Jaward, Foday M; Durham, Louise; Barber, Jonathan L; Ockenden, Wendy; Jones, Kevin C; Bruhn, Regina; Lakaschus, Soenke; Dachs, Jordi; Booij, Kees

    2004-07-15

    Air samples were taken onboard the RRS Bransfield on an Atlantic cruise from the United Kingdom to Halley, Antarctica, from October to December 1998, with the aim of establishing PCB oceanic background air concentrations and assessing their latitudinal distribution. Great care was taken to minimize pre- and post-collection contamination of the samples, which was validated through stringent QA/QC procedures. However, there is evidence that onboard contamination of the air samples occurred,following insidious, diffusive emissions on the ship. Other data (for PCBs and other persistent organic pollutants (POPs)) and examples of shipboard contamination are presented. The implications of these findings for past and future studies of global POPs distribution are discussed. Recommendations are made to help critically appraise and minimize the problems of insidious/diffusive shipboard contamination.

  5. UPTAKE AND DEPURATION OF NON-IONIC ORGANIC CONTAMINANTS FROM SEDIMENT BY THE OLIGOCHAETE, LUMBRICULUS VARIEGATUS

    EPA Science Inventory

    Uptake of sediment-associated contaminants by the oligochaete, Lumbriculus variegatus, was evaluated after 1,3,7,14,28, and 56 d of exposure to a field-collected sediment contaminated with DDT and its metabolites DDD and DDE or to a field-collected sediment contaminated with PAHs...

  6. Ecotoxicological effects of combined UVB and organic contaminants in coastal waters: A review.

    PubMed

    Pelletier, E; Sargian, P; Payet, J; Demers, S

    2006-01-01

    Organisms living in coastal waters are exposed to anthropogenic contaminants from terrestrial drainage, ice melting and maritime traffic and to enhanced UVB radiation (UVBR; 280-320 nm) caused by decreased concentrations of ozone in the stratosphere. This article reviews available information about the combined effects of UVBR and selected hydrosoluble contaminants potentially present in surface waters on marine species and especially on plankton community structure in high-latitude coastal zones. Effects of UVBR on three selected pesticides (Atrazine, carbaryl and Acifluorfen) and possible induction of phototoxicity are reviewed. Most toxicological studies have been conducted under laboratory conditions with questionable relevance for coastal marine ecosystems. Similarly, photoactivation of polycyclic aromatic hydrocarbons (PAHs) has been closely examined and reported effects on aquatic species summarized. Experiments with field-sampled communities demonstrated the complexity and the difficulty in determining the impact of multiple stressors on an aquatic ecosystem, even for ecosystems simplified by eliminating large grazers and fish. Nutrient status, specific composition and light history have influenced the different responses of planktonic assemblages exposed to enhanced UVBR and water-soluble fraction (WSF) from crude oil or to tributyltin. Plankton assemblages subjected to changes in the ozone hole were physiologically stressed and more susceptible to WSF toxicity than communities from less enhanced UVBR-impacted sites. A close relationship between phytoplankton assemblages and bacteria was observed in all experiments in mesocosms. A contaminant-induced phytoplankton crash after a bloom event may release important carbon and nutrient sources for bacteria. The magnitude of phytoplanktonic mortality induced by a contaminant probably influenced how rapidly bacteria grew over time. The transition from a herbivorous food web to a microbial food web has significant

  7. Effects of metal-contaminated forest soils from the Canadian shield to terrestrial organisms.

    PubMed

    Feisthauer, Natalie C; Stephenson, Gladys L; Princz, Juliska I; Scroggins, Richard P

    2006-03-01

    The effects of elevated metal concentrations in forest soils on terrestrial organisms were investigated by determining the toxicity of six site soils from northern Ontario and Quebec, Canada, using a battery of terrestrial toxicity tests. Soils were collected from three sites on each of two transects established downwind of nickel (Sudbury, ON, Canada) and copper (Rouyn-Noranda, PQ, Canada) smelting operations. Site soils were diluted to determine if toxicity estimates for the most-contaminated site soils could be quantified as a percent of site soil. Rouyn-Noranda soils were toxic following acute exposure (14 d) to plants, but not to invertebrates (7 d for collembola and 14 d for earthworms). However, Rouyn-Noranda soils were toxic to all species following chronic exposure (21, 35, and 63 d for plants, collembola, and earthworms, respectively). The toxicity of the Rouyn-Noranda site soils did not correspond to the gradient of metal concentrations in soil. Metal-contaminated Sudbury soils were toxic to plants but not to invertebrates, following acute exposure. Chronic exposure to Sudbury soils caused adverse effects to plant growth and invertebrate survival and reproduction. The toxicity of Sudbury soils corresponded to the metal concentration gradient, with one exception: The reference soil collected in October was toxic to collembola following acute and chronic exposure. This study evaluated the applicability of the new Environment Canada terrestrial toxicity test methods, developed using agricultural soils, to forest soils and also provided useful data to assess the ecological risk associated with mixtures of metals in soil. PMID:16566168

  8. Screening of organic and metal contaminants in Australian humpback dolphins (Sousa sahulensis) inhabiting an urbanised embayment.

    PubMed

    Weijs, Liesbeth; Vijayasarathy, Soumini; Villa, C Alexander; Neugebauer, Frank; Meager, Justin J; Gaus, Caroline

    2016-05-01

    As a marine mammal species that inhabits shallow nearshore waters, humpback dolphins are likely exposed to a wide range of pollutants from adjacent land-based activities. Increased mortality rates of Australian humpback dolphins (Sousa sahulensis) in waters off a major urbanised centre triggered investigations into the threats to these species, including their contaminant exposure. The present study utilised archived tissues from 6 stranded animals to screen for a range of pollutants (PCDD/Fs, PBDEs, PCBs, organochlorine pesticides, PAHs, organotins, essential and non-essential elements) to inform future biopsy based biomonitoring strategies. Concentrations of PCBs and DDXs in blubber of some of these animals were remarkably high, at levels near or above toxicological thresholds associated with immune- and reproductive toxicity or population declines in other marine mammals. PBDEs, PAHs, HCB, organotins, 'drins' as well as other organic pesticides were not detected, or present at relatively low concentrations. Profiles of elements were similar in epidermis compared to other tissues, and apart from some exceptions (e.g. Fe, Cr, Co, Cu) their concentrations fell within 25th-75th percentiles of cetacean baselines in four of the five animals. Non-essential elements (Al, V, Pb, Ba, Ni, Cd) were notably elevated in one specimen which may have experienced poor health or nutritional status. These data provide a first insight into the contaminant status of a rare and poorly studied population inhabiting an urbanised area. The results highlight a need for future biomonitoring of live populations, and inform on priorities in the typically limited blubber and skin sample volumes obtained through biopsies. PMID:26945241

  9. Redox processes and release of organic matter after thermal treatment of a TCE-contaminated aquifer.

    PubMed

    Friis, A K; Albrechtsen, H J; Heron, G; Bjerg, P L

    2005-08-01

    Redox conditions in heated and unheated microcosm experiments were studied to evaluate the effect of thermal remediation treatment on biogeochemical processes in subsurface environments. The results were compared to field-scale observations from thermal treatments of contaminated sites. Trichloroethene-contaminated aquifer material and groundwater from Ft. Lewis, WA were incubated for 200 days at ambient temperature (i.e., 10 degrees C) or heated to 100 degrees C for 10 days and cooled slowly over a period of 150 days to mimic a thermal treatment. Increases of up to 14 mM dissolved organic carbon were observed in the aqueous phase after heating. Redox conditions did generally not change during heating in the laboratory experiment, and only minor changes occurred as an effect of heat treatment in the field. The conditions were slightly manganese/iron-reducing in two sediments and possibly sulfate-reducing in the third sediment based on production of up to 0.20 mM dissolved iron and 0.15 mM dissolved manganese and consumption of 0.08 mM sulfate. The calculated energy gain of less than -20 kJ/mol H2 for iron and sulfate reduction as well as methane production indicated that these processes were thermodynamically favorable. Sulfate reduction and methane production occurred in the unheated microcosms upon lactate amendment. Little or no reduction of the redox level was identified in heated lactate-amended microcosms, possibly because of limited microbial activity. Because the redox conditions, pH, and alkalinity remained within normal aquifer levels upon heating, bioaugmentation may be feasible for stimulating anaerobic dechlorination in heated samples or in future field applications.

  10. Medication adherence: WHO cares?

    PubMed

    Brown, Marie T; Bussell, Jennifer K

    2011-04-01

    The treatment of chronic illnesses commonly includes the long-term use of pharmacotherapy. Although these medications are effective in combating disease, their full benefits are often not realized because approximately 50% of patients do not take their medications as prescribed. Factors contributing to poor medication adherence are myriad and include those that are related to patients (eg, suboptimal health literacy and lack of involvement in the treatment decision-making process), those that are related to physicians (eg, prescription of complex drug regimens, communication barriers, ineffective communication of information about adverse effects, and provision of care by multiple physicians), and those that are related to health care systems (eg, office visit time limitations, limited access to care, and lack of health information technology). Because barriers to medication adherence are complex and varied, solutions to improve adherence must be multifactorial. To assess general aspects of medication adherence using cardiovascular disease as an example, a MEDLINE-based literature search (January 1, 1990, through March 31, 2010) was conducted using the following search terms: cardiovascular disease, health literacy, medication adherence, and pharmacotherapy. Manual sorting of the 405 retrieved articles to exclude those that did not address cardiovascular disease, medication adherence, or health literacy in the abstract yielded 127 articles for review. Additional references were obtained from citations within the retrieved articles. This review surveys the findings of the identified articles and presents various strategies and resources for improving medication adherence.

  11. DEMONSTRATION SOLIDIFICATION TESTS CONDUCTED ON RADIOACTIVELY CONTAMINATED ORGANIC LIQUIDS AT THE AECL WHITESHELL LABORATORIES

    SciTech Connect

    Ryz, R. A.; Brunkow, W. G.; Govers, R.; Campbell, D.; Krause, D.

    2002-02-25

    The AECL, Whiteshell Laboratory (WL) near Pinawa Manitoba, Canada, was established in the early 1960's to carry out AECL research and development activities for higher temperature versions of the CANDU{reg_sign} reactor. The initial focus of the research program was the Whiteshell Reactor-1 (WR-1) Organic Cooled Reactor (OCR) that began operation in 1965. The OCR program was discontinued in the early 1970's in favor of the successful heavy-water-cooled CANDU system. WR-1 continued to operate until 1985 in support of AECL nuclear research programs. A consequence of the Federal government's recent program review process was AECL's business decision to discontinue research programs and operations at the Whiteshell Laboratories and to consolidate its' activities at the Chalk River Laboratories. As a result, AECL received government concurrence in 1998 to proceed to plan actions to achieve closure of WL. The planning actions now in progress address the need to safely and effectively transition the WL site from an operational state, in support of AECL's business, to a shutdown and decommissioned state that meets the regulatory requirements for a licensed nuclear site. The decommissioning program that will be required at WL is unique within AECL and Canada since it will need to address the entire research site rather than individual facilities declared redundant. Accordingly, the site nuclear facilities are being systematically placed in a safe shutdown state and planning for the decommissioning work to place the facilities in a secure monitoring and surveillance state is in progress. One aspect of the shutdown activities is to deal with the legacy of radioactively contaminated organic liquid wastes. Use of a polymer powder to solidify these organic wastes was identified as one possibility for improved interim storage of this material pending final disposition.

  12. Impact of storage induced outgassing organic contamination on laser induced damage of silica optics at 351 nm.

    PubMed

    Bien-Aimé, K; Belin, C; Gallais, L; Grua, P; Fargin, E; Néauport, J; Tovena-Pecault, I

    2009-10-12

    The impact of storage conditions on laser induced damage density at 351 nm on bare fused polished silica samples has been studied. Intentionally outgassing of polypropylene pieces on silica samples was done. We evidenced an important increase of laser induced damage density on contaminated samples demonstrating that storage could limit optics lifetime performances. Atomic Force Microscopy (AFM) and Gas Chromatography -Mass Spectrometry (GC-MS) have been used to identify the potential causes of this effect. It shows that a small quantity of organic contamination deposited on silica surface is responsible for this degradation. Various hypotheses are proposed to explain the damage mechanism. The more likely hypothesis is a coupling between surface defects of optics and organic contaminants.

  13. Sorption equilibrium of emerging and traditional organic contaminants in leafy rape, Chinese mustard, lettuce and Chinese cabbage.

    PubMed

    Yang, Chien-Ying; Chang, Meei-Ling; Wu, Siang Chen; Shih, Yang-Hsin

    2016-07-01

    Emerging and petroleum contaminants could transfer into food chains by plant uptake, potentially causing food security problems. To build a prediction model, the sorption equilibrium and uptake kinetics of toluene, p-xylene, naphthalene, bisphenol A, and 4-bromo-diphenyl ether in some common leafy vegetables including leafy rape, Chinese mustard, lettuce and Chinese cabbage were examined. The kinetic experiments revealed that high sorption rates were observed for these plants that had high lipid contents. For two emerging contaminants with polar functional groups, their resulting isotherms were strongly linear (R(2) = 0.92 to 1.00), indicating that the sorption was dominated by partitioning. Moreover, regression correlation showed that log Klip, the lipid-water partition coefficient, and log Kow, the octanol-water coefficient, for these organic chemicals were strongly linear-related, following the equation: log Klip = 0.894 × log Kow+0.219 (R(2) = 0.953). The correlation equation allows the prediction of the sorption capacity of plant species for an organic compound when the plant composition and the log Kow of the chemical are determined. This improved model containing different organic chemicals with a wide range of log Kow (2.73-4.80) and including emerging contaminants was established, which shows further utilization for predicting the sorption of organic contaminants by plants.

  14. Sorption equilibrium of emerging and traditional organic contaminants in leafy rape, Chinese mustard, lettuce and Chinese cabbage.

    PubMed

    Yang, Chien-Ying; Chang, Meei-Ling; Wu, Siang Chen; Shih, Yang-Hsin

    2016-07-01

    Emerging and petroleum contaminants could transfer into food chains by plant uptake, potentially causing food security problems. To build a prediction model, the sorption equilibrium and uptake kinetics of toluene, p-xylene, naphthalene, bisphenol A, and 4-bromo-diphenyl ether in some common leafy vegetables including leafy rape, Chinese mustard, lettuce and Chinese cabbage were examined. The kinetic experiments revealed that high sorption rates were observed for these plants that had high lipid contents. For two emerging contaminants with polar functional groups, their resulting isotherms were strongly linear (R(2) = 0.92 to 1.00), indicating that the sorption was dominated by partitioning. Moreover, regression correlation showed that log Klip, the lipid-water partition coefficient, and log Kow, the octanol-water coefficient, for these organic chemicals were strongly linear-related, following the equation: log Klip = 0.894 × log Kow+0.219 (R(2) = 0.953). The correlation equation allows the prediction of the sorption capacity of plant species for an organic compound when the plant composition and the log Kow of the chemical are determined. This improved model containing different organic chemicals with a wide range of log Kow (2.73-4.80) and including emerging contaminants was established, which shows further utilization for predicting the sorption of organic contaminants by plants. PMID:27085315

  15. Searching for Organics During the Robotic Mars Analog Rio Tinto Drilling Experiment: Ground Truth and Contamination Issues

    NASA Astrophysics Data System (ADS)

    Bonaccorsi, R.; Stoker, C. R.; Marte Project Science Team

    2007-03-01

    The Mars Analog Rio Tinto Experiment (MARTE) performed a simulation of a Mars drilling experiment at the Rio Tinto (Spain). Ground-truth and contamination issues during the distribution of bulk organics and their CN isotopic composition in hematite and go

  16. Simultaneous removal of organic contaminants and heavy metals from kaolin using an upward electrokinetic soil remediation process.

    PubMed

    Wang, Jing-Yuan; Huang, Xiang-Jun; Kao, Jimmy C M; Stabnikova, Olena

    2007-06-01

    Kaolins contaminated with heavy metals, Cu and Pb, and organic compoun